Soviet rounds myth vs reality

[barnbwt]

And here's an even better idea! Much more expensive than a Mk18 upper, but way cheaper than designing a whole new weapon. Same size and weight as an SMG. 20'' and 5.5 lbs.

Very impressive. You do know that the front sight & handguard will be nearly enveloped by the muzzle flash, right? 5.56s that short are beyond impractically loud, and actually begin to have substantial recoil, all for ballistics that literally approach 5.7x28 from a P90 that's a few inches shorter.

Why not an HK51k, while we're at it (308 select fire w/ 5.3" barrel)?

TCB

 

[RecoilRob]

Apparently even the Soviets knew something was up with steel at high pressures, as they incorporated an expansion groove into this prototype cartridge, 6x49 Unified;

Not sure exactly how it worked, whether an indented ring that was hammered flat by pressure to effectively lengthen the case under compression rather than tension, or an intentionally thin area to focus stress/deformation in one spot (the latter seems unlikely)

That's very interesting barnbwt! Looking at the indented case made me think of H&K delayed roller lock type action where a little bit of case creep is needed to power the action. Heck...could they even have been trying to use the Pederson delay? A case like that would be a most excellent addition to the Pederson system being it would provide a strong impulse that isn't as dependent on overcoming case friction and would also tend to prevent case head separation by giving it that additional material to easily move rearward.

I've long been enamored with Soviet designs as they often show excellent usage of materials and clever construction. Working in the Military jet engine field back in the late '80's we had some Russian engines in the back to look at...and steal ideas from. They were very clever though their coating technology wasn't up to ours and their hot sections didn't have 1/4 the life that we got...but they were easy to repair whereas ours were a total disassembly pain.

The Soviets really like to make high ROF cannons and a simple delayed blow-back type would make lots of sense and perhaps this was intended for something along these lines? Pretty neat whatever it was designed to do...thanks for posting that.

 

[grampajack]

The 7.62x25mm has been obsolescent for a while, which means something else, but I'm certain you'll just make up your own definition, anyway. For everyone else, I'll mention that most arms fall into that category, including all revolvers, and all WWII military weapons except for the M2 Browning

It was obsolescent in the years following WWII, during which time assault rifles had definitely been proven as a concept, but were not necessarily ubiquitous yet. It was obsolete by the 1960s, by which time even poor countries like Vietnam were fielding AKs in large numbers. And certainly the introduction of the AKSU in 1977 put the final nail in its coffin.

Sure...except it isn't.

7.62x25 comes in at around 500 ft-lbs. .357 Sig is more towards 600 ft-lbs. Both rounds have the same felt recoil. The .357 Sig is only marginally heavier. What's to discuss?

One of the really ironic statements you've made about what a PDW is, considering the C96 Mauser was the original PDW. (Firing probably slightly less powerful ammunition.) It's the first example of the type, but you exclude it from the class? That's just silly.

That's an arguable position, but only if it's select fire and has a stock attached. In its original inception, it's just an early semi auto pistol design. The C96 became largely obsolete at the introduction of the 1911. While the Astra and Schnellfeuer are an important part of the history of the PDW concept, they don't fit the definition of a modern PDW. In modern jargon, a PDW has a very specific set of features. The C96 is more along the lines of an SMG, like the M11, than a modern PDW.

Okay, so it just "make(s) sense" to change calibers on an existing weapon of your choice (which is laughingly heavy for what it is, and obsolescent anyway), but when I suggest producing a weapon in a caliber that has already been made by people in their garages, you think it will "cost millions". Yes, I"m certain it cost Joe Sixpack, the weekend firearms hobbyist, millions to put together his.

No, wait a minute. That's a really stupid idea, Jack, thanks for making us dumber for reading that.

If you're talking about retrofitting an existing AR like joe sixpack, then no, it won't cost millions. But you're talking about designing a whole new firearm. After all is said and done, by the time it's actually put into service, assuming the project doesn't just get scrapped halfway through, it would cost millions.

HK is already accustomed to rechambering the MP5. If they can build one in 10mm, then they can build one in 7.62 Tok. There's nothing stupid about the idea. The stupid thing to do would be to design an entirely new weapon when you can just rechamber one that's already a proven design.

And by what definition is the MP5 heavy for what it is? You're making unrealistic assumptions about these platforms. Like I said, SMGs and PDWs look light until you carry one around for a while. The thing I hear most often from people about SMGs is, "Boy, this thing's heavier than it looks." An SMG isn't significantly lighter than an AR, especially with the magazine loaded. Go look up some SMG weights.

More importantly, though, why do you think your concept would be any lighter? So you shorten the receiver a bit and 86 a 4 ounce buffer. Unless you start making crap out of carbon fiber and titanium, you're not going to beat other modern SMGs on weight.


Pistol length ARs exist. 7.62x25mm gas AR15s and M4s exist already. It's harder to find pistol-length gas 7.62x25mm M4s, but that's been a question of no major manufacturers identifying a demand for one.

http://www.youtube.com/watch?v=XBR0AT3ZCGI

https://youtu.be/KUB9nnAVl1o

The reason the 7.62x25mm is obsolescent is because no US maker is making armor-piercing ammunition for it. We're talking about using modern powder and .308-310 bullets, and the US has had over 100 years to experiment with .30. When I describe a good modern x25mm load taking a week to develop, I was being generous. Any of the major US ammo makers could probably do it in a day.

The lack of AP rounds is not what makes it obsolete. It's just an answer to a problem that no longer exists. 9mm does everything a pistol cartridge needs to do, and 5.56 does everything an intermediate cartridge needs to do. If we had nothing in our arsenals besides MP5s and M14s, then you might have a point. But as of now, you're looking to answer a question that hasn't been asked since WWII.

As Hanguns said of the Tok:

It is the only standard service pistol cartridge capable of defeating modern body armor when loaded with standard steel-core ball ammunition.

And this is an advantage because? If AP capability is needed, then 9mm AP rounds will get the job done with less recoil.

Strengths: widely available, very good penetration, capable of defeating lower-threat-level soft body armor with ball ammunition, good accuracy.

All things that can be said of 9mm, save for the armor. But again, why? 9mm AP rounds can do the same thing with less recoil.

Weaknesses: no modern pistols available in this caliber, no modern armor-piercing loads in this caliber, bright muzzle flash, corrosive ammunition and lackluster terminal performance

No. Its weaknesses are high recoil, terrible grip ergonomics in pistols, and the fact that 9mm gets the job done just as well without any of those disadvantages.

(If you know how to interpret what you're reading- I'll "break it down" for you, "grampa" (no disrespect to my actual elders. I'd guess "grampa" is maybe 23)- this equates to the 7.62x25mm being an exemplary small cartridge for some military use, mainly hampered by no new cartridge development in over 40 years.)

Now you know that's not true. When was the last time you met a 23 year old with any interest in this stuff? They're all off playing Nintendo X, or whatever the hell the new one is called.

Even with moderate commercial loads from a 4.6" barrel, it has about a 50% chance of punching through IIIA. Doubling the barrel length, and loaded with actual modern AP, a TOK M4 PDW would be a useful, cost-effective, quickly fielded system.
https://youtu.be/6_3_DBeU_HI

No, it would be a 5.5 lbs SMG with a slightly more powerful cartridge that offered no real advantages over 9mm, except that it had more recoil and muzzle flash, two things you absolutely don't want in an SMG.

 

[grampajack]

Now, conversions to AKs and ARs are easy, and have been successful (even gas operated variants), because a mag adapter is easy to affix. Growing a small magwell, especially an integra one like the MP5s, is highly difficult, and you'd be stuck with antiquated old Tok burp gun mags/drums (while excellent, the PPSH sticks and drums are incredibly heavy) and lose most of the proof of concept benefits.

Search on "Skorparev" to see the difficulty in actually building a prototype vs. talking about it.

"you have to concede that the .357 Sig is the better round"
Tok doesn't break guns like SIG, though

TCB

I don't know what a skorparev is, but I believe you. This is my point. When you set out to design an entirely new weapon, you're going out with the knowledge that it's probably going to fail. And cost everyone involved unspeakable sums of money.

So if there's something already on the shelf that can fill your needs, go for it. The Sig MPX in .357 Sig would do pretty much everything the Tok would do, only better (and the .357 Sig can actually fit into a halfway comfortable pistol grip, so you'd have cross compatabilility with your sidearms).

And if you absolutely refuse to see reason, and you absolutely must have the Tok, then use an already existing design. That way it's cheaper to begin with, and you can be relatively certain that the outcome will be good. If the FBI could get HK to make 10mm MP5s, then I don't see why they wouldn't do it in Tok for the US Army, assuming they could stop laughing long enough to get any work done.

I don't see why the Tok would be any more gentle on pistols than .357 Sig. It has the same harsh recoil impulse, so I think it would be just a matter of design. Besides, we're talking about SMGs, not pistols. And we've already established that the Tok is not going to be acceptable for a pistol because of how big the grip would have to be, so the .357 has no disadvantage here. At least making pistols in the same caliber would be possible with the .357.

 

[grampajack]

Very impressive. You do know that the front sight & handguard will be nearly enveloped by the muzzle flash, right? 5.56s that short are beyond impractically loud, and actually begin to have substantial recoil, all for ballistics that literally approach 5.7x28 from a P90 that's a few inches shorter.

Why not an HK51k, while we're at it (308 select fire w/ 5.3" barrel)?

TCB

Right you are. And you get 50 rounds with the P90, too. It is heavy though. Almost 7 lbs with a full mag.

Here's another solution:



64 gr. pill going at 2400 fps from a 10'' barrel. Not much better than 5.56, but some. Two issues, though. You don't have commonality with 5.56, and you don't get as many rounds as with the P90. I'm sure recoil is also heavier than with 5.7mm, so it would take more training to make it controllable in full auto.

 

[JShirley]

"Jack", in addition to everything else, now you're just making up stuff. It's clear you haven't actually shot the 7.62x25mm, and you are again demonstrating an inability to reasonably use other information you know, such as recoil forces and weight.

The CZ-52 recoil is well described by this reviewer:

Recoil is about the same as a poorly designed pistol shooting 9mm +P+

So much for the "high recoil". One of the videos I linked showed a controlled 70 round drum mag dump.

You think the 5.7x28mm is good because (among other things), it has good penetration, but you think the 7 62x25mm is bad because it has good penetration. Wow, Jack...that makes about as much sense as most of what you've said, so carry on. (Also, look up "obsolescent" and "obsolete", because you've demonstrated twice you don't understand their meaning.)

There are 4 lb AR-15s out there, but you think a new, purpose designed LW shorty M4 with a shorter receiver is going to somehow weigh more than a submachine gun? Again...brilliant. I'm glad you learned somewhere that SMGs can be heavy. I've known that from handling and shooting them from probably about the time you were growing out of diapers.

I'm going to strongly suggest you do a great deal more investigation on the subject of sectional density before you talk about expected cartridge performance.

There are some other worthy conversants in this thread, and I'll be happy to continue the discussion with them. You just aren't worth my time, though I'm glad you've discovered firearms, and hope you can find a good mentor to teach you safe shooting habits.

John

 

[dogtown tom]

JShirley One of the really ironic statements you've made about what a PDW is, considering the C96 Mauser was the original PDW. (Firing probably slightly less powerful ammunition.) It's the first example of the type, but you exclude it from the class? That's just silly.

grampajack That's an arguable position, but only if it's select fire and has a stock attached. In its original inception, it's just an early semi auto pistol design. The C96 became largely obsolete at the introduction of the 1911.

So..........tell us more how the 1911 made the C96 obsolete.

Good grief man......you keep digging that hole deeper and deeper.

 

[gripper]

FWIW,I shoot my PPS43C all the time(no issues in 3 years). I actually like it a lot. And,it actually feels subjectively heavier than my Zastava M92(which I ALSO have fun shooting,and do so accurately).
All things considered,I agree that a sub 4.5 pound M4gery in 7.62x25 is not only possible,but (assuming a good quality construction) would make a VERY effective PDW/carbine/pistol crossover type weapon family).
Frankly, I wish someone would not only do it,but crank up domestic production of a brass cased loading that equals or betters the S&B or the old Wolf Gold loadings.

 

[barnbwt]

That's very interesting barnbwt! Looking at the indented case made me think of H&K delayed roller lock type action where a little bit of case creep is needed to power the action. Heck...could they even have been trying to use the Pederson delay? A case like that would be a most excellent addition to the Pederson system being it would provide a strong impulse that isn't as dependent on overcoming case friction and would also tend to prevent case head separation by giving it that additional material to easily move rearward.

Not a bad idea, unfortunately it makes reloading a bit dicey: for one thing it's hard to apply that crimp groove, and two it'll fatigue crack after like two uses I'd bet. For one-shot steel case or an army with more copper than it knows what to do with, I don't know why it wouldn't be desirable apart from extra cost. I suspect it is useful in high pressure rounds like the Unified or autocannon (assuming they also use it, because their grooves were up at the shoulder not the base) where either the forces or the size of the machine make it difficult to form a perfectly rigid breech lock. For a rear-locking autocannon bolt, the distance between bolt face and receiver lug can be several inches or even longer, and I'll bet the amount of allowable flex of a breechface before case failure does not scale linearly upward (i.e. the same five-thousandtsh flex may crack a 37mm the same as a 308, because in both cases it is only the extreme rear of the case body doing the stretching since the rest of it is glued to the chamber walls under pressure)

Furthermore, if we're talking about armor penetration, then the 5.7 has the Tok beat by a mile. And so does 9mm AP for that matter. The Tok can penetrate level II, whereas the 5.7 can penetrate multiple layers of IIIA.

You do realize the Tok out there is at best a simple steel-cored FMJ round nose bullet, right? If driven as fast as that (heavier) 9mm +P+++BBQ kaboominator, why on Earth would a narrower projectile not shear through armor more effectively, projectile design being equal? Tungsten rod in an aluminum projectile body would be horrifyingly effective, same as it is for any other bullet (and why we aren't allowed to do that as civvies). Same as how an expansion-oriented Tok round is pretty darn effective at expanding. Not rocket science. I love the 5.7 as much as anyone, but the thing is honestly at low-end 9mm power levels, whereas Tok is at the high end; 5.7's marginally higher velocity may be able to get through some armors more effectively --I would think soft armor especially-- but would have far, far less juice left to do anything else once getting through. Not saying the 5.7 isn't adequate for handling an armored target, but the whole point of the round is that it is the very minimum power level to do so, and more powerful options would obviously do even better.

"I imagine a ~90 grain solid copper pill loaded in a 357 Sig would smoke the Tok in just about every category."
I said "just about every category," so I'm obviously conceding that the Tok has better penetration. My argument, though, is that's not an advantage for most real world applications.

Not just 'better penetration,' much better penetration, and far better ballistics even at fifty yards. You get a bullet above a certain aspect ratio of width to mass, and it becomes very ineffective, especially for the kinds of armor penetration you bring up. Velocity is critical to exceeding the local material properties of the armor, stressing it faster than it can dissipate the forces into the surrounding area, but you still have to apply enough bulk energy to break them at the impact point. Wider bullets are never preferable to this goal, and making them lighter so as to get above a critical velocity is counterproductive, since the only result is very marginal initial penetration gains at the rapid expense of ballistic reach (i.e. unreliable performance at different ranges as the bullet slows down rapidly) and poor penetration once inside the dense body of the target.

The French actually developed these nifty bronze ring-airfoil bullets, looked like a short hollow cylinder, that had a plastic plug "sabot" that fell out once outside the barrel. Incredibly high velocities, I want to say north of 2500fps, and would punch armor ruthlessly. Oddly enough, the projectiles tumbled and fell to Earth almost immediately beyond contact distance, which was claimed to be a 'feature' for urban police use (in reality it meant your gun was useless past thirty yards or so) and had very poor terminal penetration that you'd expect from a lightweight non-expanding bullet. But they sure would mess up that first 1/2" or so of body armor better than most 9mm standard pressure rounds!

I don't want overpenetration. I want reasonable penetration with a decent wound cavity. I can get better overall terminal performance from the 90 grain .357 Sig for the same level of felt recoil.

You've shot 110gr and 158gr 357 magnums, right? Can you even imagine how loud & fiery a 90gr SIG would be to shoot? Recoil wouldn't break your wrist, but it'd be so fast & violent it'd sting the hell out of your hand, I'd bet. Five-seven pistol times two, easily; guaranteed flinch-maker. I also find it humorous you are so concerned with "just right" penetration considering your advocacy for SBR 5.56 loaded with (I assume) varmint bullets capable of performing at the reduced muzzle velocities. I suppose handguns operate under different rules, or something.

Be wary of chasing low penetration in lieu of hydrostatic shock or stretch cavity effects. Those phenomena are very unreliable, and subject to all sorts of factors. The PS90 shooting SS197 has been shown to both zoom right through with little deflection or cavitation, as well as to shred apart like the Columbia on re-entry, as well as to explode like the Challenger on the very surface of the gel. Whether your target is fat or muscular, or wearing a leather jacket, can make all the difference, along with where you hit him. The frangible bullet tech is still where early hollowpoints were in my opinion, when clothing would plug them up & stop them from expanding reliably. The concept is sound, but it's not quite ready for service yet, unless the other benefits are overwhelmingly desirable for your needs (they are for mine, but I also practice multiple hits since I know performance is likely to be "on average" equal to 9mm, but highly variable)

Right you are. And you get 50 rounds with the P90, too. It is heavy though. Almost 7 lbs with a full mag.

Here's another solution:
[overbore short barrel AR-variant]


64 gr. pill going at 2400 fps from a 10'' barrel. Not much better than 5.56, but some. Two issues, though. You don't have commonality with 5.56, and you don't get as many rounds as with the P90. I'm sure recoil is also heavier than with 5.7mm, so it would take more training to make it controllable in full auto.

I'm guessing this was a 6.8spc or something? Once again, the fundamental issue is the powder to bore volume is rather high, meaning lots of boom and flash, even if a fatter bore does tend to mitigate this somewhat at the expense of higher recoil (since fatter bore means you need a wider, heavier bullet unless you're shooting super-poor BC lightweight bullets quickly or super slow normal-BC bullets), a conundrum that becomes more and more untenable as the barrel gets shorter & weapon weight decreases. The whole point of a PDW is that, like a cartridge for a full-length rifle, the cartridge is designed around a desired bore length/volume. The whole point of an SMG was originally to be more reliable than a machinegun and be man-portable, then to be far cheaper than locked-breech weapons, and has finally come to blend in with the low-end PDW concept with the advent of closed-bolt SMGs (thus eliminating the potential for almost all cost savings).

So..........tell us more how the 1911 made the C96 obsolete.

No kidding. Luger, maybe, Walther, maybe-er. In reality, it was a number of various home-grown slide-based weapons that replaced the Bolos in nations that actually had money to spend (read: NOT Soviet Russia or China) and in far greater quantity issued, until the High Power made "Browning" synonymous with "auto pistol" forever more. Blowback 32acps were still the most common sidearm for decades, though. It's really funny he brought up the 1911 as the C96's replacement, since the C96 had an enormous international following by practically everyone but the Americans, whereas the American 1911 was oddly ignored by the rest of the planet (Norwegian Nazis excluded, of course)

There are 4 lb AR-15s out there, but you think a new, purpose designed LW shorty M4 with a shorter receiver is going to somehow weigh more than a submachine gun? Again...brilliant. I'm glad you learned somewhere that SMGs can be heavy. I've known that from handling and shooting them

I would not be surprised if his experience comes from 9mm ARs. I know more than a few who adopted the "these things are worthless & terrible" attitude after shooting them, and realizing that the large bolt makes them both heavier and harder-kicking. Very few have shot a properly-designed SMG, fewer one with a delayed or locking breech system, and fewer still a fully automatic subgun vs. a short barrel carbine with muzzle brake. There would be a lot larger focus on rate of fire than ballistics, and flash/concussion than AP ability were that the case.

It is no coincidence the silencer epidemic tracks the SBR M4gery fad almost exactly

TCB

 

[barnbwt]

All things considered,I agree that a sub 4.5 pound M4gery in 7.62x25 is not only possible,but (assuming a good quality construction) would make a VERY effective PDW/carbine/pistol crossover type weapon family).

\
Whaddaya know, they did!

https://en.wikipedia.org/wiki/Bizon_SMG

Empty (I assume) weight is 4.63 pounds, and that's with a ton of needless neo-Soviet steel and a ridiculous 64rnd drum magazine. SIG MPX is supposedly heavier than this, though I suspect one of them is lying since it is all-around smaller, aluminum, and uses polymer mags (maybe the barrel is really fat?). Steyr TMP is 2.9lbs, the B&T MP9 variant with a stock is about 3lbs. Clearly barrel is the predominant factor in any case, which as I said is why it makes a lot more sense to go PDW or pistol cartridge below a certain barrel length for overall efficiency; fighting this only results in unpleasant firebreathing, deafening carbines that are even harder to control.

The MP9 is always the gun I point to when fools claim SMGs are no smaller than AR15's. The P90 when someone goes on about how small & compact the MP7 is (gosh, HK, I just don't know why NATO passed over your $4000 wunderwaffen for a dooded-up blowback with more powerful projectile at <1/4 the cost; you were right to stamp your feet and cry to your politicians until Germany vetoed the 5.7's adoption ). Sadly, there is no way to demonstrate via the internet just how much more unpleasant an SBR AR in any caliber is indoors compared to a pistol/PDW carbine, to the point I've been repeatedly assured on this forum that a 9mm pistol is no louder than a braked 14" AR15. Right.

TCB

 

[JShirley]

I have fired thousands of rounds of 5.56x45mm from real M4s. I guarantee that I would gladly take a 10" barreled 7.62x25mm AR-15 for home defense instead (especially since the introduction of such an arm from a major maker would guarantee at least a few good modern loads almost instantly). I hate heavy muzzle blast. I even have a Noveske "Fire Pig" on the first M4gery I had built, despite the 16" barrel.

Also, the Bizon in 7.62x25mm is something I've wanted for years. I had read that the drums weren't available in the caliber, but Max says otherwise.

It is interesting to note that the Bizon is based on a shortened AKS-74U receiver, and shares 60% parts commonality, despite being a blowback instead of gas weapon. 85% commonality with the same action on my proposed AR-based PDW seems like a perfectly reasonable goal.

John

 

[barnbwt]

Don't be too broke up about the drums, I doubt they work better than a Calico's . The AK is kind of special in that its carrier/piston is almost exactly the right weight for a blowback, as is, which makes conversions so easy. The AR on the other hand requires a lot of beefing up of the carrier, and the result is still a bit light to avoid heavy recoil, despite making the gun much heavier.

There is a MAC upper that takes PPSH drums, however...

 

[grampajack]

...

"Jack", in addition to everything else, now you're just making up stuff. It's clear you haven't actually shot the 7.62x25mm, and you are again demonstrating an inability to reasonably use other information you know, such as recoil forces and weight.

The CZ-52 recoil is well described by this reviewer:

So much for the "high recoil". One of the videos I linked showed a controlled 70 round drum mag dump.

Have you ever shot +P+? Not only is it hard on guns, but the recoil is on par with .357 Sig 115 grain.

You think the 5.7x28mm is good because (among other things), it has good penetration, but you think the 7 62x25mm is bad because it has good penetration. Wow, Jack...that makes about as much sense as most of what you've said, so carry on. (Also, look up "obsolescent" and "obsolete", because you've demonstrated twice you don't understand their meaning.)

You haven't been listening, nor do you seem to know enough about ballistics to understand. Just because a round penetrates well in body armor doesn't mean it penetrates well in human tissue. The 5.7mm, properly designed, will pierce IIIA armor at 50 yards and penetrate no more than 12-13'' in tissue. That's because the bullet tumbles and expends all of its energy in the target, whereas the 7.62x25 just ice picks it. The 5.7mm, because it's going 2400+ fps, causes a 2-3'' permanent cavity. Even in HP form, the Tok can't come anywhere near that. The 5.7mm also beats the Tok's effective range by 50m.

There are 4 lb AR-15s out there, but you think a new, purpose designed LW shorty M4 with a shorter receiver is going to somehow weigh more than a submachine gun? Again...brilliant. I'm glad you learned somewhere that SMGs can be heavy. I've known that from handling and shooting them from probably about the time you were growing out of diapers.

Good grief, man, have you even built an AR before? Do you have any idea what it takes to get an AR to 4 lbs? Not only is it expensive, but the finished product makes sacrifices in strength and reliability. Not only do you have to turn the receivers into swiss cheese, but you have to reduce the mass of the operating system. And shortening the receivers isn't going to drop more than a few ounces.

As for diapers, something tells me you never grew out of them.

See, I can make snarky little insults, as well. But perhaps we could just cut the BS and act like adults here?

I'm going to strongly suggest you do a great deal more investigation on the subject of sectional density before you talk about expected cartridge performance.

I don't have to talk about "expected cartridge performance" because there's plenty of concrete data on all the cartridges being discussed here. I'm not speculating; I'm relating the facts.

There are some other worthy conversants in this thread, and I'll be happy to continue the discussion with them. You just aren't worth my time, though I'm glad you've discovered firearms, and hope you can find a good mentor to teach you safe shooting habits.

Nonsense. You just realized you're full of it, and you can't support your position. So now you're using the "it's not worth my time" defense as a cop out.

John

 

[grampajack]

Be wary of chasing low penetration in lieu of hydrostatic shock or stretch cavity effects. Those phenomena are very unreliable, and subject to all sorts of factors. The PS90 shooting SS197 has been shown to both zoom right through with little deflection or cavitation, as well as to shred apart like the Columbia on re-entry, as well as to explode like the Challenger on the very surface of the gel. Whether your target is fat or muscular, or wearing a leather jacket, can make all the difference, along with where you hit him. The frangible bullet tech is still where early hollowpoints were in my opinion, when clothing would plug them up & stop them from expanding reliably. The concept is sound, but it's not quite ready for service yet, unless the other benefits are overwhelmingly desirable for your needs (they are for mine, but I also practice multiple hits since I know performance is likely to be "on average" equal to 9mm, but highly variable)

No. First of all, the SS197 is a civilian version of 5.7mm that is intentionally designed to be ineffective. The real deal is restricted by FN, even though it's technically legal in the US. It's penetrator is basically the same as what you see in M855. It's a mild steel not subject to the AP laws.

But even the SS197 doesn't "explode." Out of the PS90 even, it will barly expand. The vmax was designed to do over 3000 fps from a 24'' varmint barrel. It's an incredibly poor bullet for 5.7mm.

Here's what modern 5.7mm looks like, at FN LE restricted velocities. https://www.youtube.com/watch?v=xbMlxdp1cSw

 

[JShirley]

Nonsense. You just realized you're full of it, and you can't support your position. So now you're using the "it's not worth my time" defense as a cop out.

Kid, I've already amply proven my point to everyone who understands the subject*. I was never a huge fan of the platform, so it's only been 19 years since I got my first AR-15, well after I had regular access to a legal SMG. That was about 3 years before I enlisted as a very old active duty infantryman after 9-11. About six years after that, I found myself on a tiny Special Forces Firebase in Afghanistan. The Special Forces team had access to a variety of weapons, and the 18B on the team told me that he would happily have carried the PPSh-43 they had in inventory, instead of his issued 10 inch barreled M4, but he couldn't get access to 7.62x25mm ammunition. (Maybe I should have led with that story, but I have a feeling that you're so full of what you think you know from reading on the internet, that you still wouldn't have paid any attention.) Staff here was aware of my deployment and they have seen lots of pictures of me during that deployment, and have mailed packages to me at my military addresses in Afghanistan, and they actually know me personally. No one knows you or your ( lack of) Bona fides. Further, I am easily found on AKO, though I'm no longer an infantryman.

I am currently on my way back to the People's Republic of Maryland, where I will retrieve all of my AR-15s, including three rifles and a pistol in 3 calibers that I built, and take them back to my residence in a gun-friendly state.

(still)John

* if you want an easy example of actually understanding the subject, read this post again.

 

[Acera]

Wait, wait. I have a money making proposal that will bring in more than $98 an hour while working at home.

I've been building a squared off ring in the back yard. Figured I would put lysanderxiii and jack under contract for the first event and make a small fortune selling tickets, tv rights, t-shirts, sponsorship's and concessions. Now it looks like John wants a shot at the title also??

If Jack finds a partner, (which may be hard to do) we can have a tag team match. That would be an epic no holds barred fight to the finish.


How much do you think we should charge for pay-per-view, $100-$250???
(THR members get 10% off with coupon)


Think we could get Tula or Wolf as a sponsor? And maybe Budweiser? (Been eating a lot of popcorn while reading this thread and getting thirsty.)


.

 

[JShirley]

God, that would be so beautiful. I have to make every reasonable (and some unreasonable) effort to not actually injure the offenders in the facility that I work in.

Everyone else in the thread probably understands this, but once you reach a certain level of experience from actually shooting living things, you stop believing in Magic Bullets and other fairy tales. Penetration is about the only fairly consistent constant, especially with non expanding bullet designs. Once you throw fragile, highly velocity-dependent projectiles into the mix, all bets are off.

( anyone with enough historical perspective would of course understand this. I have a custom 22-250 fast twist rifle, but if I ever load for intermediate range anti-personnel use, I will hope for [but not trust in] the dramatic expansion and potential fragmentation of the round I shoot. That projectile, will of course be a heavy .224 projectile that will have been tested many, many times against living targets over years, and it will impact the target at 300 yards at higher velocity than any 5.7 millimeter rounds exit the barrel)

 

[Vern Humphrey]

I've been building a squared off ring in the back yard. Figured I would put lysanderxiii and jack under contract for the first event and make a small fortune selling tickets, tv rights, t-shirts, sponsorship's and concessions.

Better have paramedics standing by -- for the spectators who collapse from boredom.

 

[grampajack]

Kid, I've already amply proven my point to everyone who understands the subject*. I was never a huge fan of the platform, so it's only been 19 years since I got my first AR-15, well after I had regular access to a legal SMG. That was about 3 years before I enlisted as a very old active duty infantryman after 9-11. About six years after that, I found myself on a tiny Special Forces Firebase in Afghanistan. The Special Forces team had access to a variety of weapons, and the 18B on the team told me that he would happily have carried the PPSh-43 they had in inventory, instead of his issued 10 inch barreled M4, but he couldn't get access to 7.62x25mm ammunition. (Maybe I should have led with that story, but I have a feeling that you're so full of what you think you know from reading on the internet, that you still wouldn't have paid any attention.) Staff here was aware of my deployment and they have seen lots of pictures of me during that deployment, and have mailed packages to me at my military addresses in Afghanistan, and they actually know me personally. No one knows you or your ( lack of) Bona fides. Further, I am easily found on AKO, though I'm no longer an infantryman.

I am currently on my way back to the People's Republic of Maryland, where I will retrieve all of my AR-15s, including three rifles and a pistol in 3 calibers that I built, and take them back to my residence in a gun-friendly state.

(still)John

* if you want an easy example of actually understanding the subject, read this post again.

Thank you for your service. I wasn't in the infantry, nor did I go to Iraq. In fact, I was discharged after 6 months for asthma. Which is probably a good thing, because the 5 miler in Airborne school probably would have killed me. People in my unit who went on to graduate told me it was at a pretty good clip.

I also knew several guys older than me in basic (and I wasn't exactly straight out of high school myself), and I had great respect for them. I wouldn't dare try to join the Army nowadays, that's for sure, even if I were technically still qualified. What's the cutoff these days? The Air Force maybe...

With all that said, most of the guys I knew in the Army didn't know anything about guns that they didn't learn there. Even most of the senior NCOs didn't know much. While being discharged, I worked the battalion night desk, and had many hours to chat with the NCOs about various gun related topics. I also had the unfortunate luck of getting a 5th SF guy as a drill sergeant, and he said all kinds of stuff I wouldn't agree with.

My point is that simply being in the Army, regardless of the MOS, doesn't automatically make one an expert, or even qualify their opinion. If we were debating small unit tactics, then I would defer to you. But we're debating the intricacies of terminal ballistics and firearms design. There's nothing in your MOS that makes you automatically more qualified than the average gun nut.

And now we get the full story. Your whole argument is based on one comment made by one weapons sergeant. However, depending on the context, I might agree with him. But not based on terminal ballistics, but rather reliability. This isn't the time or place, but I will argue the unreliability of DI SBRs all day every day. If given the choice between a PPSh and a Mk18, I might be tempted to choose the PPSh, depending on the conditions. But I would take an AKSU over the PPSh, as well as a P90, MP7, MP5, Colt SMG, UMP, Grease Gun, pretty much anything really.

I also tend to believe that he was speaking somewhat sarcastically, so as to emphasize his distaste for the Mk18. Kind of like how people say they'd rather drive a Yugo than a Hyundai. They don't mean it literally; they're just using hyperbole to communicate their distaste for something. Without being there, I cannot say, but my feeling is that you're taking his comment somewhat out of context, as well as assigning way too much value to it. I'm sure more than a few guys in his unit would have disagreed with him, assuming he was even really serious in the first place.

As far as my qualifications, I have none. My degree is in IB and linguistics. My only claim is that I'm a life long gun nut from a family of life long gun nuts. If there was any money in it, I would have been a gunsmith. Part of me regrets not getting an engineering degree and trying to work for one of the major gun manufacturers. But then again, I probably wouldn't enjoy designing those kinds of guns anyways. Like you, I have some different ideas about things, although not quite as off the wall as issuing 7.62x25 to the Army! Just saying it in my head makes me chuckle. Come on, man, even the Russians don't use it anymore. And that should really be a clue! These are the same people who still use a rimmed cartridge in a semi automatic rifle, for crying out loud! They don't change anything unless it's a problem.

It seems to me that there's a status quo here, and that certain people have the luxury of being able to say just about anything without challenge. Furthermore, those people get hostile should anyone have the audacity to disagree with them. What do the rules say, Attack the argument, not the person? Thus far, I've been called an idiot in no uncertain terms, and now you're accusing me of being a kid. If my argument is so weak, then why do you feel the need to disparage me? It just clouds the issue and makes you look weak.

Here's why your argument is flawed:

9mm does everything that 7.62x25 can do at SMG ranges. There just isn't much call for an SMG with a range of 150 meters. And the disadvantages of the round FAR outweigh its advantages.

1. Recoil is heavier, making it more difficult to control in full auto. I'm not saying it's impossible, or even unmanageable, but it's a fact. Most importantly, it means bigger groups. I've never shot it in full auto, but I think I'm safe assuming it would be similar to the difference between shooting an SMG in 9mm and .40 S&W, if not more.

2. The round is too long to comfortably fit in a pistol grip, especially for female shooters, which is now a factor more than ever thanks to the Obama administration. With that said, even I wouldn't be comfortable with it, and I have big hands. Truth be told, anyone under 6,4 wouldn't be truly comfortable with such a pistol, even if it were single stack.

This means that it could never replace 9mm, but would be in addition to 9mm. That's a whole new round to be put into the Army's supply chain, which is already pretty complicated as it is. And, if by some strange glitch in the time-space continuum the Army actually did what you're suggesting, the chance of any of the other branches adopting it are zero. That would complicate the issue even further.

3. An entirely new weapon would have to be created. Even if it were based on the AR, you'd have to make so many changes that you would effectively be creating a whole new firearm. This isn't like going from the M4 to the Mk18, or even the Mk12. Your claim of 85% compatibility is ludicrous. To get anywhere near that, you'd basically just be rechambering the Colt SMG in 7.62x25.

You weight goal of 4 lbs is also unrealistic, especially since you're planning on using the existing PPSh mag design, as opposed to designing a new one from polymer. But, let's say you could design a viable SMG that was 4 lbs. That same SMG could just as easily be chambered in 9mm. If the MP5 is too heavy, then the solution isn't to look to another caliber, but to another SMG. As of now, I don't see anything substantially better than the MP5. Even the UMP in 9mm still weighs 5 lbs, and it's mostly polymer. Besides, there's not much difference between 4 and 5.5 lbs. If your unit couldn't handle a 5.5 lbs MP5, then no SMG is going to be any better, except maybe something like an M11, but even that's danged heavy for what it is, not to mention it's just a terrible weapon. Long story short, your proposed SMG wouldn't have made any difference in the situation you described. They would have been just as well off with MP5s, and if that was unmanageable, then M9 pistols.

4. In the rare event that body armor is a factor, 9mm AP rounds can get the job done with less recoil. There's no reason to look to another round based on its ability to pierce body armor. I would, however, be in favor of making 9mm AP standard issue. The terminal effect is excellent, and you never know when WWIII will break out. The US could find itself facing armored targets at any time.

Look, I'm not saying your idea is impossible, or that there is no situation in which an extended range SMG might be valuable. I'm simply saying that the disadvantages far outweigh the advantages. The Soviets obviously reached the same conclusion years ago.

 

[JShirley]

Here's the thing: my idea is not based on that one comment. But a career SF weapons sgt who was not especially unhappy with his issued weapon also thought highly enough of the little Soviet's round's close-range performance that he wished he could use it (our ammo Connex had 7.62x39mm for our local allies, but no 7.62x25).

I am an officer now, besides having a lifelong interest in military history, a history degree, and a degree in history education. I understand that wars are frequently- perhaps even usually- won with logistics, and I am one of the first people to point out that the Soldier's individual weapon is far down the list of the most important things in warfighting. (There's this thing called "the myth of the American rifleman" that centers around the mistaken idea that individual Soldiers with rifles won our wars. That hasn't been true since our first battle against the British, where patriots fired over half a million shots, succeeding in injuring more of their fellows than they did British soldiers!) I say that to agree that in general ammo commonality is more important than having a more effective round.

If you go back and look again, what I said was that it would have made much more sense to have had a 7.62x25mm M4 PDW than make the P90. I do think my suggestion is imminently workable, and would be useful for everyone except for infantry, but that doesn't mean I am suggesting another round be put in US inventory.

As far as many in the military not actually knowing much about firearms, that's definitely true. I had been shooting for almost 26 years when I enlisted, which was certainly not the norm.

Attack the argument, not the person?...now you're accusing me of being a kid. If my argument is so weak, then why do you feel the need to disparage me? It just clouds the issue and makes you look weak.

Here's what you're not getting: I was talking about "your argument", which is clearly based on things you have read instead of experienced, and on some faulty assumptions. These things point to both a lack of enough genuine shooting experience and also youth/immaturity. There's a misconception that all opinions carry the same weight which is not at all true. It is true that everyone is welcome to their opinion, however, educated opinions are more valuable than less educated / inexperienced ones. You have been given some very nuanced, intelligent rebuttals to some ideas that you have that are incorrect. You have refused to acknowledge them or more properly to acknowledge their validity. There's really not much more to say about that than you're wrong and we don't feel like repeating ourselves much more.

John

 

[grampajack]

...it would have made much more sense to have had a 7.62x25mm M4 PDW than make the P90. I do think my suggestion is imminently workable, and would be useful for everyone except for infantry, but that doesn't mean I am suggesting another round be put in US inventory.

If you're going to make an SMG in something that's not 9mm, thereby adding another round to the confusion, then make it something that is substantially better in more than one category.

The 5.7mm has the extended range you're wanting, 50 meters more than the Tok in fact. It also has outstanding penetration in armor and good penetration in barriers, such as window glass, heavy clothing, sheet metal, etc.

Its terminal performance is truly excellent for a pistol round. The wounds at close range look similar to a 5.56, albeit with less penetration. But you've only got so much energy in a pistol caliber, so you can't have everything, and 13'' of penetration in flesh and bone gets the job done. Like I said, I've seen pigs shot with 5.7mm that were just plain nasty. A hole you can put your hand inside of and exploded ribs and shoulders that make you cringe. Even a Tok HP could never come anywhere close to that level of damage. I used to have a link to the videos, but I lost it. I'll have to call the guy and ask him. He caught some flak for posting them, so they're private. I used to be down on 5.7mm, too, but his videos turned me around and quick. I then quickly realized that all my assumptions were based on FN's "sporting rounds." Even the SS198LF, which is technically one of the "LE only" rounds, isn't good stuff. They claim it's military grade, but you can find it all over the internet, so it's really kind of a joke. And even SS190, the supposed AP round, is outdated. Solid copper handloads at SS190 velocities are truly awe inspiring.

It's also substantially lighter and the recoil is nonexistent. You get 50 rounds at 1 lbs, as opposed to 30 rounds of 9mm or Tok at, what, 1.3 lbs (ish)? That's a 60% increase in capacity with a 23% decrease in weight.

Ballistics are similar to SBRs, especially those under 10''. Ergonomics are improved. Not only is it easier and more accurate to shoot offhand, but the stock is effectively collapsed all the time, so it's ideal for shooting from a vehicle. And not having a banana mag sticking out makes it easier to carry.

Honestly, had the Germans not blocked NATO standardization of the P90 with their inferior MP7, I think it would be more heavily used. If I were a pilot or vehicle crewman, it's what I would want. Or if my job made carrying a carbine unnecessary, but there was still a danger of being attacked.

Here's what you're not getting: I was talking about "your argument", which is clearly based on things you have read instead of experienced, and on some faulty assumptions. These things point to both a lack of enough genuine shooting experience and also youth/immaturity.

Tell me where my argument is flawed. Did I say anything that is objectively untrue? If I got a fact wrong, then I'll gladly correct myself. But you were out of line calling me "kid." It was clearly meant as an insult, and it was extremely disrespectful. And it's something you know to be untrue. Like I said, all the kids in this country are off playing Nintendo, not debating terminal ballistics on a gun forum. Besides, what does it matter? Eight or eighty, my argument is sound. Attacking me based on your perception of age is an ad hominem.

 

[JShirley]

Pointing out your lack of experience is not an attack, it's an observation, one that's absolutely relevant when it comes to understanding things about how bullets perform once they strike an object. Further your lack of ability to understand nuance not only annoys the absolute crap out of me it makes me not want to read anything else you have to write because you're frankly astonishingly annoying to converse with, despite having obviously above average IQ.

In short, you're obviously able to read, but frequently seem absolutely unable to understand, which means there's no real point to conversing with you.

 

[barnbwt]

I do declare this disagreement may only be resolved in single combat, or worse yet, math

TFB is supposedly putting together what is called a "design space" of many intermediate cartridges, which is what is needed. Basically, it is a multi-dimensional surface defined by various parameters, I think TFB is doing five or so. When slices are taken of this surface in two dimensions, you get plots between two variables, say speed & distance, for your various bullets (or a 3D plot if a family of data series are used, like multiple barrel lengths or bullet weights for a given chambering). What's really cool is when you start compiling lots of data, sometimes you see patterns. Plot a 3D point graph of bullet weight, diameter, and barrel length for commerically available platforms & loads across all chamberings, and you'll find clusters of points at the various weapon families, pistols in pistol chamberings, pistol caliber carbines, PDWs, carbines & assault rifles, battle rifles, big game rifles, shotguns, LMGs, HMGs, autocannon, and artillery.

I'd wager any stacking of variables will show these same clumps, with a few outliers, and within these clumps a 'normal' distribution of some sort that favors a popular common configuration like the M4 or Glock 19. I'd further wager these focal points also tend to be near points of inflection for other combinations of variables, like overall weight to recoil to kinetic energy, since humans are by nature good at optimizing complex phenomena. Lastly, I surmise there are focii among the pertinent variables that have not been exploited, or were once popular but fell from favor. Explaining why one 'ideal' succeeds and others fail, or why non-ideal clusters of design occur at random would make for a very interesting math/engineering/history discussion.

I can no longer converse this way in a rat's nest of opinion & quote trees, with at least two other fools as verbose as I am, long since strayed from the OP somewhere around mid page one. You guys feel I should start a thread on;
1) How to reintroduce the 7.62x25 as a competitive service cartridge?
2) Design goals & tradeoffs of a PDW round?
3) Real performance expectations of 5.7x28 rounds?
4) Physical mechanics of armor vs. meat penetration?

Pretty sure 3 & 4 will result in an immediate lock if not ban 'round these parts

TCB

 

[gripper]

I am cool with options#1 and #2.

 

[JShirley]

While I do believe a short M4 in 7.62Tok would be a great piece, my whole initial point was that making it would have had many benefits (almost certainly including dramatically wider adoption due to much lower cost and identical manual of arms) not realized by FN making the P90 instead. <shrug>

In the final analysis, penetration is the single most important characteristic for a military projectile.

If you want to start a thread about authentic, realistic goals for a PDW, that might be a worthy topic.