Hydraulic recoil spring?

[F-111 John]

To the OP's question, I just read in another thread about Walther's new CCP coming out soon. It appears to use the identical H&K P7 gas piston system to lower recoil and reduce the recoil spring weight for easier chambering.




Not hydraulic, but the same principle that the OP desired.

 

[1911Tuner]

To the OP's question, I just read in another thread about Walther's new CCP coming out soon. It appears to use the identical H&K P7 gas piston system to lower recoil and reduce the recoil spring weight for easier chambering.

Gas-delayed blowback.

 

[barnbwt]

Toasty fingers and a Zamak frame; yummy

"If frame battering didn't exist, nor extraction problems due to pistols unlocking too soon while pressure are still too high, then any locked breech 9mm handgun should be able to shoot +P+ ammo without a problem. Or Israeli submachine gun-only ammo, for that matter."
Can you say "bolt thrust?" Or frame/slide fatigue cracking? Tuner's right that peening of the frame does not seem to be the failure mode on these guns (or most others, for that matter). That doesn't mean other failure modes aren't still active.

"At some point, you can start getting failures to extract, because the pressure in the case is pushing the brass against the chamber walls, making the case stick. In my book, this qualifies as the barrel unlocking too soon while pressures are still too high."
At high pressures, the brass is deformed and it cannot spring back from the walls; just look at sticking cases in revolves, long after pressures have dropped to ambient. If what you described was happening, pressures would be so high that initial extraction would bulge and rupture cases, which the Glock fiasco showed was really due to chamber design rather than action timing.

An interesting test, if Tuner is still into abusing 1911's , would be to test to case failure a pistol in a standard ransom rest, and in one where the slide is held fixed rather than the frame (to keep the action from cycling). If the unlocking test fails sooner, you could logically conclude it had something to do with the failure; if a fixed breech 1911 blows out nearly the same way as the auto-loader, you'd know that chamber support and case head strength were the players (I kinda think you'd get primer failure long before either, though )

TCB

 

[1911Tuner]

Can you say "bolt thrust?" Or slide fatigue cracking?

Bingo.

Everybody worries about the frame when it's the slide that catches all the hell.

 

[Tirod]

As for gas delayed actions, the P7 was not marketed as a high round count range gun. It was a LEO issue gun for personal protection. Yes, it got hot after a few hundred rounds. It's not a duty gun for extended range use, and commenting on the heat issue is simply misplacing it into a use it wasn't designed or intended to work in.

It was a small frame gun with the express purpose of meeting a specific carry requirement for use after the Munich terrorist incident.

As for it or a newer version having a lighter spring, it goes to not having any other unlocking complications to increase friction in operation. It's a fixed barrel gun. I propose it simply doesn't need more spring to pick up a cartridge and chamber it. All it has to oppose forward momentum is the gas delay plug and rails. Said plug is vented in the reloading cycle, at worst drawing against some vacuum into the cylinder.

Not to intrude on 1911tuners dialectic, it's more about slide weight than springs. From what little I have read, it's not the longslide 1911's, it's the chopped down versions with much lighter slides that have cycling issues.

As for frame battering, it's not the first time I've read a seriously experienced 1911 user debunk the need for expensive springs, guides, etc. There are makers who sell things because they can, not because the gun needs it. I only have to point out the AR market today in general, and the "tactical" charging handle specifically. There is no track record of the issue charging handle being a problem child, and with the bolt hold open, the use of the handle from magazine to magazine is nearly non-existent. If the bolt is held back on the last shot, why do we need expensive and massively constructed charging handles with all the ornamental machining?

Because, like springs and buffers, a lot of people who base their knowledge on inexpert opinion see them and think they are 1) COOL and 2) BETTER THAN YOURS.

Again, it's not because you need one, it's because they are for sale, as if that is reason enough to justify them.

I would go so far as to say the majority of CNC billet machined auto parts sold to the younger driver's have just as much reasoning behind them. They are mostly there to separate cash from that demographic, with no documented and tested results whatsoever. Just lots of evocative prose and a pretty girl in the photo.

It's call marketing.

 

[JRH6856]

Bingo.

Everybody worries about the frame when it's the slide that catches all the hell.

So, for clarity, do heavier springs or shock buffers do anything to protect the slide?

 

[1911Tuner]

So, for clarity, do heavier springs or shock buffers do anything to protect the slide?

Nowhere except the slide's impact abutment...and it's about as much concern as the frame's.

 

[BenFoo]

Ive just started messing around with .45Super in my 1911.

The .45Super uses a different case to allow for the additional pressure.

The higher rated recoil springs are to allow for proper functionality of the pistol not to keep the gun from harming itself. Thats why things like slide weight, metal type and finish also come into play.

The 1911 needs so much slide travel/timing to properly extract and chamber the next round. If the timing is off you start getting FTE and FTL.

So, changing the recoil spring out is to offset the additional "power" to make sure the timings are still correct. More so than the damage to the frame/slide. Thats, imo, a secondary attribute of using a properly tuned spring is no impact damage.

Bit more about selecting a proper recoil spring by Nic Taylor. Some good slow-mo shots in there too.

http://youtu.be/w3UVLm2GajI

 

[JRH6856]

OK, spring weight can certainly affect recovery for second shots. And in theory, heavier loads can produce more muzzle rise which can be balanced by a heavier recoil spring pulling the muzzle back down—not softening the recoil, but equaling it in a subsequent (not coincident) action in the opposite direction. Or in Nic's case, a lighter spring works better. That depends on the shooter, so load, spring, and shooter are a 3 part balancing act.

And the theory of frame impact damage is still a chimera.

 

[GLOOB]

Yes, in a recoil-operated locked breech firearm, the bullet is always going to leave the barrel before the breech unlocks as long as the bullet is within the normal weight range for caliber.

That doesn't matter, either. The locked breech pistol is a closed action/reaction system...

The weight of the bullet absolutely matters. The slide unlocks after a small fraction of an inch of travel. The reason that the bullet travels more than 4-5 inches by that time is because it's so much lighter. You increase the weight of the bullet enough, and that is no longer the case.

...It's like an equation. Whatever is done to one end is done to the other end. i.e. A heavier bullet will have a lower rate of acceleration and so will the slide. If pressure and force increase, acceleration rates increase on both ends and vice-versa.

Exactly. You contradicted yourself in the very next sentence. Saying the weight of the bullet doesn't matter is equivalent to saying that the weight of the slide doesn't matter.

Everybody worries about the frame when it's the slide that catches all the hell.

Slide or frame, what does it really matter? The gun takes abuse and wears out.

If frame battering doesn't exist, then why are certain SIG aluminum alloy guns (226 IIRC) known to wear out and crack the FRAME at around 25,000 rds? You can't use a 1911 as empirical proof of what handguns do. It should be obvious that which part of the gun fails first depends on how it is built and is not the same between different guns.

At high pressures, the brass is deformed and it cannot spring back from the walls; just look at sticking cases in revolves, long after pressures have dropped to ambient.

When this has happened to me, the cases easily dropped out of the chamber after the event. I dunno, maybe something else was going on, but I know I'm not the first person to describe this mode of failure before.

 

[1911Tuner]

So, changing the recoil spring out is to offset the additional "power" to make sure the timings are still correct. More so than the damage to the frame/slide. Thats, imo, a secondary attribute of using a properly tuned spring is no impact damage. (Because .45 Super)

Any time you push the stresses beyond those that a machine was designed for, you decrease the life of that machine. The 1911 was designed for the stresses imposed by the .45 Auto cartridge. Even with modern steels, the Super is still too much for it...but the main concern is still with the upper barrel lugs and mating slide lugs, and the slide breechface rather than the impact abutments.

So, changing the recoil spring out is to offset the additional "power" to make sure the timings are still correct.

Extra power doesn't have any effect on timing. Timing is mechanically fixed and the timed event occurs at the same point in the cycle regardless of speed.

Time is a function of speed and distance. The "Extra Power" does have an affect on that.

 

[1911Tuner]

The weight of the bullet absolutely matters. The slide unlocks after a small fraction of an inch of travel. The reason that the bullet travels more than 4-5 inches by that time is because it's so much lighter. You increase the weight of the bullet enough, and that is no longer the case.

It's a closed system. Whatever you do to one end, you do to the other end. Wrap your head around that.

The bullet will still have the time and distance to reach the muzzle before the barrel completely disengages vertically. If you keep moving the powder charge and bullet weight (and length) up to the point that the pressures blow the case, the gun will simply let go before the bullet gets to the muzzle. Peak pressures occur within the first half-inch of bullet travel. If it's gonna blow, that'll be where it happens.

The other possibility is to keep using a longer and heavier bullet until there's not enough room in the case for a sufficient powder charge to get the bullet to the muzzle...actually a point of diminishing returns on the pressure...and the whole cycle would very likely come to a stop.

 

[Sol]

^ When 2 pieces of material are butted up against each other one moves and one is stationary you will get wear.

When one of those pieces of metal is harder than the other like an aluminum frame and a steel slide, it wears out faster.

 

[1911Tuner]

When 2 pieces of material are butted up against each other one moves and one is stationary you will get wear.

Nobody's arguing against that. The question here is...how rapidly will that wear/peening/deformation occur? You can beat a 2-foot diameter steel ball flat with a tack hammer if you stay at it long enough.

 

[Walt Sherrill]

Slide or frame, what does it really matter? The gun takes abuse and wears out.

Agreed... but the whole point of this discussion had to do with recoil control mechanisms, and as the discussion progressed, it subtly changed to address why certain people believe that the recoil spring PROTECTS the frame of the gun.

The points you're minimizing are in support of the argument that recoil springs have a functional role, but protecting the frame (or the slide) isn't one of them.

 

[BenFoo]

So, changing the recoil spring out is to offset the additional "power" to make sure the timings are still correct. More so than the damage to the frame/slide. Thats, imo, a secondary attribute of using a properly tuned spring is no impact damage. (Because .45 Super)

Any time you push the stresses beyond those that a machine was designed for, you decrease the life of that machine. The 1911 was designed for the stresses imposed by the .45 Auto cartridge. Even with modern steels, the Super is still too much for it...but the main concern is still with the upper barrel lugs and mating slide lugs, and the slide breechface rather than the impact abutments.



Extra power doesn't have any effect on timing. Timing is mechanically fixed and the timed event occurs at the same point in the cycle regardless of speed.

Time is a function of speed and distance. The "Extra Power" does have an affect on that.

I agree. I was trying to put it into easier terms. Perhaps my word choices were wrong. Was trying to speak to the point of using recoil springs to tune for proper function. Lots of things effect that, including the shooter.


While I will primarily be firing 45acp, i wanted to be able to carry the same firearm with a slightly more potent load for in the woods for bear. I selected a 255g hardcast .45Super. Should be more than sufficient for black bear in my area.

45 Super Ammo - 255 gr. Hard Cast FN (1,075fps/M.E. 654 ft.lbs.)
vs
45 ACP +P Ammo - 255 gr. Hard Cast FN (925 fps/M.E. 484 ft. lbs.)

I plan to shoot enough to select the correct springs for functionality and verify....and then hope I never have to shoot anymore in .45Super. If I do, that means things have gone sideways in the woods and I could care less if the firing of 16rds of .45Super chews off 1000rds of normal 45acp wear from the 1911.


If you select a 1911 that also gets chambered in .40sw, .38Super or SIG .357, the PSI produced for those is still higher than .45Super. So yes you will get increased wear, but I do not think it will be dramatic.

 

[GLOOB]

If you select a 1911 that also gets chambered in .40sw, .38Super or SIG .357, the PSI produced for those is still higher than .45Super. So yes you will get increased wear, but I do not think it will be dramatic.

Pressure does not cause wear. You can shoot .357 SIG out of a 45 ACP handgun all day long. Short of the chamber failing, you do not get more wear from higher cartridge pressure. It's primarily recoil in general, and momentum in particular, that drives wear.

It's a closed system. Whatever you do to one end, you do to the other end. Wrap your head around that.

Lol. No. When you change the weight of the bullet, you are changing the system.

Yes, a heavier bullet will accelerate slower, and thus the slide will accelerate slower. That does not matter. We are interested in the relative change. When you double the weight of the bullet, the slide will necessarily move back about twice as far by the time that bullet reaches the muzzle. Just the same as would happen by decreasing the slide mass by half. The actual time/speed at which this point occurs will be far different, of course, if we are keeping pressure constant and thusly having vastly difference projectile velocities.

Whether or not this is a moot point in a 1911, specifically, you may know that answer. But take my comment at face value, and you will hopefully see where we can agree.

Peak pressures occur within the first half-inch of bullet travel. If it's gonna blow, that'll be where it happens.

This is a very good point and I am inclined to agree.

 

[BenFoo]

Pressure does not cause wear. You can shoot .357 SIG out of a 45 ACP handgun all day long. Short of the chamber failing, you do not get more wear from higher cartridge pressure. It's primarily recoil in general, and momentum in particular, that drives wear.





Lol. No. When you change the weight of the bullet, you are changing the system.



Yes, a heavier bullet will accelerate slower, and thus the slide will accelerate slower. That does not matter. We are interested in the relative change. When you double the weight of the bullet, the slide will necessarily move back about twice as far by the time that bullet reaches the muzzle. Just the same as would happen by decreasing the slide mass by half.

Perhaps not directly but if the whole thing explodes due to being over pressure your wear will be accelerated from functional to where did my gun go.....

.45 ACP (21,000 PSI)
.45 ACP +P (23,000 PSI)
.45 Super (28,000 PSI)
9mm (35,000 PSI)
.40 S&W (35,000 PSI)
10mm (37,500 PSI)
.460 Rowland (40,000 PSI)
.357 Sig (40,000 PSI)


.357Sig is almost double the max pressure than .45ACP. Im sure you knew that but without a firearm being rated to fire that higher pressure....the "wear" might be immediate.


Most of the guns that have ready available conversions are over-engineered, as a whole, and can take additional pressures.



Yes chamber pressure is the main concern.




We seem to be getting farther from the OPs main question here as people pick apart small details in others posts.

 

[1911Tuner]

When you double the weight of the bullet, the slide will necessarily move back about twice as far by the time that bullet reaches the muzzle.

I'll try again.

With the standard round, the base of the bullet is about a 10th inch forward of the muzzle when the slide has moved a 10th inch.

And the barrel still has another full 10th inch to go before the lugs vertically engage.

Even if you could stuff a 460 grain bullet into a .45 Auto case and still have enough room for powder to produce the pressures necessary to drive it to 830 fps...which is doubtful...it would still have plenty of time and distance to escape before the barrel unlocked.

And if the double weight produced half the velocity...the slide would likewise be moving at half velocity and the bullet would still escape before the lugs could vertically disengage.

Because....

It's a closed system.

Whatever you do to one end you do to the other end.

But the pressures involved in driving a 460-grain bullet even to 415 fps from a .45 Auto case would probably unwrap the gun before the bullet moved more than an inch and well before the barrel reached the point of disengagement.

And I'm outta words...and the thread has drifted off of springs...so I'll stop arguing this hypothetical situation that can't be proven in reality...mainly because there's not enough room in a .45 case to accommodate a 460-grain bullet.

 

[GLOOB]

With the standard round, the base of the bullet is about a 10th inch forward of the muzzle when the slide has moved a 10th inch.

Sorry, wut? Can you please explain how you figured this out? And how this possibly applies to all handguns, universally?

I did some measurements on my Glock 27, which I have had the extraction problems on hot loads, and I found something very interesting.

Glock 27 slide + barrel weight = 413 grams.
180 gr bullet = 11.7 grams.
Distance of slide/barrel movement before the barrel lugs contact the locking block = approximately 50 mics* +- 2 mics, or 1/20th of an inch. (Measured with the depth stop on my calipers on the back of the slide).

According to this calculation (which I'm not a physicist it might be wrong) 0.050" x 413 grams/11.7 grams = 1.76". If you don't factor in the recoil spring, this would mean the bullet is still in the barrel by the time the barrel hits the locking block. Of course it takes a much longer distance than 0.05" before the breech opens any considerable distance, but I find this very curious in terms of potential to affect accuracy and extraction. (The hot loads I had extraction problems with were also all over the map, even factoring in the flinch factor, but they were top notch in my FNX). I think it's safe to say the 17-18 lb recoil spring is a rather significant factor in this specific gun and that it does more than just return the slide to battery.

The way the spring factors in is more complicated. A spring applies force over distance, but in this case we are also concerned with the duration in time. If you slowly pressed the slide of a gun back with a ton of force, the frame would also just move back. Even with a hand holding it, the frame would press farther back into the shooter's hand before it started moving in relation to the slide. But with a higher impulse, the frame would not move as much in that first fraction of an inch of travel. The inertia of the frame would start to factor in. Thus, the slide:frame movement would be greater in the all important first 1/10th of an inch. This is one of the reasons why I reckon that hotter loads could make this gun unlock too soon, even though the bullet weight is the same.

*Edit: sorry, made a mistake in measurements. Will update with an edit.

Distance before hitting the locking block is right on 90 mics. This changes the distance of bullet travel to 3.17", which is well out of the barrel. So now this muddies up my previous reasonings. The extraction problem could be exacerbated by the way the Glock extractor rod/spring is setup, causing some inertial inefficiencies, but I still want to think pressures can be too high and/or the brass still needs just a little time to shrink back for extraction in the moments after the bullet has left the barrel. As for inaccuracy of those hot loads, I don't know.

My FNX is harder to measure, because there's no good spot to put the calipers. But it appears to be around 150-190 mics depending on how I measure, and the weight of slide+barrel is 468 grams, with a similar weight spring. This gives it a much larger margin of error.

 

[JRH6856]

Sorry, wut? Can you please explain how you figured this out? And how this possibly applies to all handguns, universally?

It applies to the 1911 which is the handgun under discussion.

And FWIW: A 300gr Speer Deep Curl HP (#3974) over 6.3gr Power Pistol will produce just over 800fps at just under 21,000psi. (435ft/lbs, PF:242) Recoil is...stiff. (in a 1911)

 

[GLOOB]

Sorry, wut? How does this apply to the 1911 in particular, even? The 1/10th inch and 1/10 inch seems too convenient to where it might be incorrect assumption. I'd like to see some calculations.

If I didn't know better, I might think Tuner pictures that the slide only starts to move after the bullet leaves the muzzle, and at that point the slide and bullet travel in opposite direction at the same speed, like some kind of first-grader's idea of how things work.

Icing: if the barrel were only 1/10th an inch out of the barrel at that time, then how can people shoot 255 grain bullets.... that would put them approximately 0.4" from the muzzle at that point. Does a 1911 barrel hit the locking block at 1/10th inch?

Also, if the 1911 cuts things that close, what happens when people put extended barrels in said 1911? And how do people lighten/mill their slides and still shoot regular weight ammo?

 

[JRH6856]

No, the slide does start to travel before the bullet leaves the barrel. But the barrel does not unlock from the slide before the bullet leaves the barrel. So the breech remains locked while the bullet is in the barrel and does not unlock until after the bullet has left allowing pressures to drop to ambient level.

The 1911 is not a straight blowback where the inertia of the mass of the slide and the stiffness of the spring keeps the breech closed but can be defeated by increasing the power of the load. The breech is locked which produces a delayed blowback action. The point in the cycle when the barrel unlocks is controlled by the barrel link, not by the speed of the bullet and the slide or the mass of the bullet or the slide. It is not a matter of time and force, but of position, The barrel always unlocks at the same position, no matter how slowly or quickly the slide gets it there.

Another factor in the cycle is that while the expanding gasses are applying two equal forces in opposite directions, driving the less massive bullet in one direction, and the more massive slide and barrel in the other, the friction between the bullet and barrel is a countering force causing the bullet to pull the barrel in the opposite direction than the slide is pulling it. This countering force and resulting delayed action lasts until the bullet has left the barrel.

 

[Walt Sherrill]

The point in the cycle when the barrel unlocks is controlled by the barrel link, not by the speed of the bullet and the slide or the mass of the bullet or the slide. It is not a matter of time and force, but of position, The barrel always unlocks at the same position, no matter how slowly or quickly the slide gets it there.

Seems as though this would be true with other guns using other variants of the basic Browning Short-recoil system, as well.

While most guns don't have the 1911-style link, the barrel in most of those guns must move DOWN a set path, and the speed at which it moves is not the relevant factor, but how far the barrel must move (in the slide) before it has dropped enough to unlock the barrel.

The part in all of this I don't understand or know how to address is how different barrel lengths might affect the geometry and physics we're talking about:

If you use the same load and a similar weight recoil spring, where will the bullet be in a longer barrel compared to a shorter barrel as the round is ignited and the process begins. It's already been made clear that some of the very compact guns are harder than longer guns to be made to run consistently and reliably. (I've used everything from 12 lbs. to 22 lbs in my CZs with the only change I've really noticed (other than changes to the recoil impulse) is that the heavier springs make the slide much harder to rack...)

In some of our earlier discussions about springs, (where folks claim that well-made springs don't wear out that quickly -- a point that can and has been debated ad naseum), I have noted that Rohrbaugh suggests changing the R9 [small 9mm gun] recoil spring every 200 rounds or so.

Based on what we've discussed here about springs, recoil reductions systems, the earlier comments about how Larry Brown tweaks his "work" gun, I've come to believe that Rohrbaugh's guidelines about spring replacement this is NOT to protect the gun, but to assure that the TIMING of the recoil process will NOT be thrown out of kilter.

Any explanations or observations about how barrel length changes might affect this whole process?[/I]

 

[JRH6856]

I haven't looked at what happens in a longer barrel, at least not a non-ported one. And a ported barrel provide pressure relief. My first thought is the friction/drag element is still in play to an extent, but my second thought is that that is probably insufficient if the barrel gets very long.

Maybe 'Tuner has some insight.