Hydraulic recoil spring?

[GLOOB]

Well, it isn't sneaky, but it's looking at two things instead of one thing.

Like looking at a bullet and a slide/barrel?

what if these collisions involved heat or potential energy storage (like loading up a recoil spring that's caught on an empty mag, for example)?

Here's a more striking question. Why can no one on this thread admit it when they're wrong? Except me. You can qualify it, even. Say "maybe."

"Maybe I'm wrong."

"I might have misspoke."

"You might be right."

"Ohh, I didn't think of that."

"Ohh, I see."

"Ohh, you know what, I got a C in physics. Now, I see why."

Try it. It is liberating.

 

[mls]

My head hurts...following this thread. I am done here.

 

[barnbwt]

Just bound and determined to get the thread locked, huh? I've self-censored myself against snark/etc. mightily in this post; please show me the same courtesy.

"because our particular problem doesn't happen to require a specific consideration for friction, because..."
Which means conservation of momentum is sufficient in this case. I said we were in agreement. The numbers match; no need for egos to get involved.

If you still have a point that you think needs to be argued, articulate it in terms of how it makes the 1911 operated differently from what I've described so far (and please relate what you think my theory described, and how it differs from yours, specifically, and I'll try to do the same --arguing two sides of the same point, is pointless)

I'd love to hear everyone's thoughts on my JRH-inspired revelation regarding the camming-link's unexpected effect on slide momentum

TCB

 

[GLOOB]

Sorry for spoiling the gun talk.

I'll remove myself from this thread so the gun guys can get their gun fix. My apologies for trying to impose my point of view of the universe unto thee, barnbtw, JHr66, Tuner, et al. My only consoldation is I am sure I would have been banned by now if anything I have said was incorrect.

Edit: that didn't work so well.

 

[barnbwt]

You think people need to be wrong to be banned? Check out (b)Arfcom, sometime . I appreciate the discourse, GLOOB, I really do; making me second-guess myself and re-examine my precepts is a good practice, just gotta keep things reaaalllll mellow... math is bad enough as it is without adding aggravation to the mix (why do you think the FBI's having a hard time finding good hackers that don't smoke pot? ). At the end of the day, who's right doesn't matter if the numbers track with observed reality, where we defer to the real authority on the subject

You forgot 45_auto, btw

TCB

 

[GLOOB]

I didn't include 45 Auto for reasons that should be obvious to him. Cheers. Yeah, speaking of FBI hackers, I should go mellow out for a bit.

And by the time the lugs are disengaged, the link angle is pointing quite a bit backwards. This is where the new theory comes in. The link can only apply load along the direction defined between its pivot points. As the barrel starts camming down, the link's load vector points more and more forward. It's actually pointing forward at ~30deg or so when the lugs are still engaged, as best I can tell, which means a chunk of the load pulling the barrel down is also pulling it forward while the lugs are engaged! That explains everything! That even explains why over-loaded guns damage their links in addition to their extractors!

Now, at this point, the bullet's gone and there's no risk of kaboom, so the only design impact of this last-minute slow down of the barrel/slide is to reduce the energy that must be absorbed by the recoil spring.

Now, then. This is a very good read, barnbtw. I never knew that 1911's even suffered from damaged links, at all. But I suppose if you habitually overloaded a Glock, it would be the barrel lug and locking block that would be similarly damaged.

so the only design impact of this last-minute slow down of the barrel/slide is to reduce the energy that must be absorbed by the recoil spring.

One other thing it would do is it might help to spread out the recoil, compared to a blowback. But there are at least 2 other reasons why a blowback has more felt recoil.

 

[Nom de Forum]

This thread, more than any other, has made me very thankful I stopped being concerned about understanding the minutia of the 1911 and started trusting in the dependability of my Glocks. Thirty years ago I would have been in the middle of the melee with 45_auto, barnbwt, Gloob, JRH6856, et al. to define the one true gospel of 1911 operating principles. This discussion has convinced me that sometimes ignorance is bliss and trust based on observation sufficient. I share the following sentiment:

mis - My head hurts...following this thread. I am done here.

 

[JRH6856]

This thread, more than any other, has made me very thankful I stopped being concerned about understanding the minutia of the 1911 and started trusting in the dependability of my Glocks.

Well, based on GLOOB's comparisons, perhaps you understand something about your Glocks as well.

 

[Nom de Forum]

Well, based on GLOOB's comparisons, perhaps you understand something about your Glocks as well.

Until my head stops hurting I think I am temporarily suffering from being unable to comprehend as much as I did know about 1911s and Glocks. Ouch! I hurts just to use my brain to type 1911 and Glock.

 

[Walt Sherrill]

The original question was, I think, something like, "WHY MUST RECOIL SPRINGS be so strong that they make racking the slide difficult?"

Answers varied from -- "because it's necessary to make the gun function and to protect the frame"; that was later expanded to include "other components") to "to operate the slide in preparation for the next shot, and not much else.") Those comments led to a long series of responses that talked about the physics of pistol function, some of which was very interesting.

For those of us who are not mathematically inclined and hampered in our appreciation of some aspects of physics, I feel I must ask: have we answered the original question? Why must the springs be so heavy. And have we answered the question about why guns shooting rounds like the .460 Rowland require MUCH heavier recoil springs?

I'd like to get some PRACTICAL use out of this discussion and understanding when a spring is heavy enough would be a good thing to know.

If we have, I've missed those answers, somehow -- but it won't be the first time I've missed seeing the forest for all the trees.

 

[BenFoo]

The original question was, I think, something like, "WHY MUST RECOIL SPRINGS be so strong that they make racking the slide difficult?"

Answers varied from -- "because it's necessary to make the gun function and to protect the frame"; that was later expanded to include "other components") to "to operate the slide in preparation for the next shot, and not much else.") Those comments led to a long series of responses that talked about the physics of pistol function, some of which was very interesting.

For those of us who are not mathematically inclined and hampered in our appreciation of some aspects of physics, I feel I must ask: have we answered the original question? Why must the springs be so heavy. And have we answered the question about why guns shooting rounds like the .460 Rowland require MUCH heavier recoil springs?

I'd like to get some PRACTICAL use out of this discussion and understanding when a spring is heavy enough would be a good thing to know.

If we have, I've missed those answers, somehow -- but it won't be the first time I've missed seeing the forest for all the trees.

I think ALL 460Rowland 1911 conversions have a compensator.

In the case of the Clark conv, I'm pretty sure it ships with a 24lbs and 20lbs recoil spring. Using the incorrect spring will cause an autoloading pistol to not run correctly. The comp keeps you from having to use a crazy spring rates in the specific recoil spring.

45Super article
http://www.realguns.com/archives/020.htm



460Rowland from Clark
http://www.clarkcustomguns.com/rowland.htm

 

[barnbwt]

Since the spring does not prevent the gun from damage or cycling open properly, deductive reasoning would suggest it is there solely to close the action strongly enough to reliably feed/chamber the round and hold the action in battery. Since Rowland operates considerably outside the recoil levels of what the 1911 was designed for, the same logic may not apply; the springs in that case may be necessary to prevent damage or unduly harsh recoil. I would also submit that the much-higher recoil would apply much stronger forces than originally encountered on the camming link, especially in a light/short slide & barrel configuration, but the recoil spring is extremely unlikely to have much effect that early in the cycle

So the strong spring may prevent peening/other damage or harsh recoil for 460 Rowland, but cannot so protect the link, and also provides no protective measures of significance at all in the 45ACP configuration. It for sure does not change the timing of the gun perceptibly (bolt thrust moving the slide back vs. the simultaneous spring pressure is laughably enormous)

"but it won't be the first time I've missed seeing the forest for all the trees."
well, there are a lot of trees on this thread, after all... I for one, at least learned how the heck the 1911 link down works, though, so I'm happy

"I think ALL 460Rowland 1911 conversions have a compensator."
Ah, so that's how they reduce the enormous applied recoil early in the cycle; that'll do it . Without the brake, I imagine you'd have frame/slide/link damage very quickly. Oddly enough, the braking forces are identical to the bullet friction as far as the barrel/slide/lugs are concerned; raises their stresses significantly (but obviously not to the point of failure, unlike the likely case of the links or frame/slide)

TCB

 

[GLOOB]

deleted

 

[GLOOB]

There's the million dollar question. I will take a crack, even though no one else on the planet will agree.

Why must the springs be so heavy. And have we answered the question about why guns shooting rounds like the .460 Rowland require MUCH heavier recoil springs?

Why must the springs be so heavy?

They don't have to be heavy. Do you know how to tell when to change the recoil spring in a Glock 17? When you point the gun up and let the slide return to battery, slowly, and it doesn't close all the way! That's not very heavy.

In a .460 Rowland, you are loading to higher muzzle velocities than the gun was designed. You can look at it many different ways, but the end result is the slide will recoil at a faster speed and chamber pressures will be higher.

Slide/frame battering: When the faster moving slide reaches the end of travel, it will hit harder than the gun was designed. There can be some stress damage or peening.

Extraction: When the case is extracted, the slide will be pulling the case out at a slightly earlier point in time, with a slightly higher residual pressure, and it will rip the case out at a slightly greater slide/frame speed. This puts more stress on the extractor and can cause failures to extract, broken extractors, and even case rims being ripped through.

Locking Lugs: the higher residual pressure and earlier (in time) unlocking have the effect of increasing wear on the locking lugs and the link. The barrel is being made to unlock faster and while under greater force between the lugs. Even if you think pressure is long gone the instant the bullet leaves the muzzle, the simple fact that the barrel essentially has a controlled collision with the frame in a short period of travel means the faster the slide travel, the greater the acceleration and stress. While the barrel is decelerating and dropping, the slide "wants" to keep moving; this increases the force between the locking lugs while the barrel is camming. Also, as barnbwt noted, the link(?)has a large role in arresting the barrel.

Recoil: with a stock spring, the slide will carry more speed/momentum when it hits end of travel, and this might make felt recoil worse.

If you put in a heavier spring you can alleviate all of these problems, to some degree. But a heavier recoil spring slows the speed of the slide when it's near the end of travel relatively more than it can reduce the initial velocity of the slide, which is closer to where a lot of this bad stuff is happening. So there's a limit to the "spring fix". At some point, you will end up trading extraction problems for limpwrist malfunctions and stovepipes. You will also have a faster cyclic rate, and this can cause feed malfunctions where the mag spring can't push up the next cartridge in time for the slide to pick it up. Also, you can theoretically get some slide/frame battering from the return trip being too violent, as well as a more urgent problem of the firing pin lighting off the subsequent rounds by inertia. So you might have to beef up the firing pin spring, too.

If you wanted to take things up to an even higher level, you would need to increase the mass of the slide. (Of course, only if the chamber and locking lugs can handle that extra pressure). This is why no one makes a 9mm with the slide weight of an LCP. Even if there was someone who would find the recoil manageable, it could not be made to function reliably, let alone durably, with today's materials and methods.

Well, I have to take that back. If you increased the slide travel before the barrel unlocks, you could possibly get there. Picture a gun that is racked. Now, return the slide to battery. But where it would normally stop, it keeps going forward for another, say, half inch. With this setup, there is an increased delay before the barrel unlocks, and the recoil spring might also have a more efficient effect on reducing slide velocity by the time extraction takes place. The extra slide travel should potentially reduce the cyclic rate, as well, given a suitably lighter spring. But, then there's yet another problem with a light weight slide, even if it weren't for extraction and durability problems... Not only is there more felt recoil, but there's more recoil. The lighter the slide, relative to the bullet, the greater the share of the kinetic energy that it will receive. This has the effect of reducing muzzle velocity of the bullet and increasing recoil to the shooter. There is a very obvious diminishing return on reducing slide weight for caliber.

If you could increase the mass of the slide, it could fix all the aforementioned problems without so much of the drawbacks and limitations of using just a heavier spring. Also, with a 1911, you have the option to increase the weight of the mainspring, too. This will reduce the initial slide velocity by some degree without some of the negative consequences of increasing recoil spring weight.

And have we answered the question about why guns shooting rounds like the .460 Rowland require MUCH heavier recoil springs?

I believe the answer to this is no, because of the word "we." Agreement is not likely. This is just the way I see it.

 

[JRH6856]

The original question was, I think, something like, "WHY MUST RECOIL SPRINGS be so strong that they make racking the slide difficult?"

And the bottom line answer is, On a standard 1911, or Commander, in .45ACP or 9mm, they don't. They will run fine on as light as 7 lbs when everything else is in spec.

With cartridges and configurations (longer or shorter slides) outside of the standard designed configuration, YMMV.

 

[barnbwt]

"Extraction: When the case is extracted, the slide will be pulling the case out at a slightly earlier point in time, with a slightly higher residual pressure, and it will rip the case out at a slightly greater slide/frame speed. This puts more stress on the extractor and can cause failures to extract, broken extractors, and even case rims being ripped through.

Pressure: the higher residual pressure and earlier (in time) unlocking have the effect of increasing wear on the locking lugs and the link. The barrel is being made to unlock faster and while under greater force between the lugs. Even if you think pressure is long gone the instant the bullet leaves the muzzle, the simple fact that the barrel essentially has a controlled collision with the frame in a short period of travel means the faster the slide travel, the greater the acceleration and stress. While the barrel is decelerating and dropping, the slide "wants" to keep moving; this increases the force between the locking lugs while the barrel is camming."

I know we pretty much proved 45acp is gone from the barrel in nearly all circumstances worth noting before link-down. Does anyone feel like running numbers to see if this happens to be the same case for Rowland (I honestly have no idea)? My intuition says the slide simply flies back harder, making both link-down (and link-tension) and extraction/ejection far more violent. That gets you broken parts (possibly even lug rounding/wear as the forward-pointing component of link tension pulls on the tip of the lugs as the slide/barrel come apart) and jacked-up brass, same as an over-gassed auto

And if we think about it from a top-level view, a recoil action is gas operated; the barrel the piston, obviously. Just like any gas-op action, if you increase the power (pressure and its duration) you will dump too much energy into the cycle of the action and break stuff and tear up cases, even though the timing (absent extreme circumstances) doesn't become dangerous from early unlocking.

TCB

 

[GLOOB]

I know we pretty much proved 45acp is gone from the barrel in nearly all circumstances worth noting before link-down. Does anyone feel like running numbers to see if this happens to be the same case for Rowland (I honestly have no idea)? My intuition says the slide simply flies back harder, making both link-down (and link-tension) and extraction/ejection far more violent.

Agreed. If you could see inside the gun and record everything in slow motion up to the point where the bullet reached the muzzle, and you were to shoot a regular 230 gr 45ACP and then a 230 gr .460 Rowland out of the same, stock, gun, you would be very hard pressed to tell the difference. The footage would be very similar, except one would play back faster. I could provide... nevermind. Let's just call this my uninformed opinion.

Of course the time that passes between the bullet leaving the muzzle and the barrel unlocking is going to be shorter with the Rowland, because it IS faster. And the Rowland will have more pressure that needs to be relieved in this shorter timeframe.

Here, we would need those "numbers" to figure out the difference in time. I'm not sure how you would go about estimating how pressure in the barrel/chamber drops over time, though. It would be nice if that slow motion video of the 1911 would continue to show the muzzle blast developing after the bullet is gone.

 

[JRH6856]

I'm not sure how you would go about estimating how pressure in the barrel/chamber drops over time, though.

You use an internal ballistics simulator like QuickLOAD.

 

[GLOOB]

Haha, nice. This seems to show pressure while still in the barrel. At least we know there's only a chamber pressure of around 2500+ psi by the time the bullet is at the muzzle, if I'm reading this correctly.

If you have a .45 caliber tube, 5 inches long, pressurized to 2500 psi and you pull the cork, then what happens in the next 0.2-0.3ms? There's still powder burning, at this point, I am guessing. But it seems like a good place to start.

I don't suppose you could plug in a .460 Rowland load, too? And/or something with a slower powder.

 

[JRH6856]

Muzzle pressure is 2581 psi with 93.97% powder burned.

You get some muzzle flash and unburned powder expelled.

Pressure MAX= 15137psi. Muzzle Velocity= 830fps

Bullet travel time i= 0.749ms. Distance = 4.375" (bullet does not start at breech)

Linkdown and extraction has not yet begun so the case is still fully chambered.

 

[JRH6856]

I don't suppose you could plug in a .460 Rowland load, too? And/or something with a slower powder.

This data is a simulation only do not use for loading.

460 Rowland. 230g FMJ RN, 8.9g Ramshot Silhouette.
PMax = 34906psi,
Velocity = 1134fps,
Bullet exits at .519ms
Muzzle Pressure = 3821psi
Powder Burn 99.65%

 

[GLOOB]

Other than my own first hand experience, here are a few other examples of extraction problems that may possibly be related to overpressure and/or light recoil springs.

HK with slight overload of Bullseye
http://thefiringline.com/forums/showthread.php?t=480247

BHP after swapping a lighter recoil spring and upping ammo PF.
http://www.brianenos.com/forums/index.php?showtopic=111717

Ruger SR9 with a max dose of Power Pistol
http://www.thehighroad.org/archive/index.php/t-723896.html

A Glock with a healthy dose of Bullseye
http://www.reloadersnest.com/forum/topic.asp?TOPIC_ID=13656

Being a lower pressure to begin with, 45ACP might be more immune to this maybe-phenomenon.

Coincidentally, my two different loads this happened with experienced only intermittent failure to extract with the empty case left halfway in the chamber, held in place by the next round trying to get in from below - same story in these examples. In both of my loads, the gun worked fine when the charge was backed off. Mine both happened in Glocks, FTR. A 9 and a 40. I was a tad over max on both.

 

[JRH6856]

Not sure what we are doing here, but higher pressures can cause cases to bond to the chamber walls. Especially if the walls are rough as in the R51s. Under normal pressures, the case relaxes as pressure drops, but the bonding at higher pressures can slow this relsaxation and leave the case sticking to the chamber wall during extraction. And if the resistance is too high, the extractor can either slip over the rim or rip the head off the case. The same thing can happen if extraction occurs before the bullet leaves the barrel.

And yes, I would expect to see this more with 9mm than witl .45ACP due to the difference in operating pressures.

FWIW, the pressure difference may be one reason JMB went to the cam block instead of a barrel link in the BHP. Or maybe not.

 

[GLOOB]

^Ohh, that's good. I see. So higher pressure may make the case take longer to retract because of higher "adhesion" to the chamber wall. I didn't think of that.

So this is a function of peak pressure? This would explain why this occurs even with fast powders like Bullseye. Mine both happened with relatively slow burners, and I was surprised to see BE figure into two of the above cases.

My problem load in my Glock 27 worked great in an FNX. I'm gonna go out on a limb and call the Glock chamber at least as smooth or smoother. But the FNX quite obviously to me has longer delay before unlock. I picture this: High peak pressure imprints the case to the chamber. Longer delay before extraction means more time for the case to "peel" away, even though pressure drops quite rapidly once the bullet leaves the muzzle. ?

Yes, that surely sounds good JRH. I was missing a big piece. It makes sense that this failure can be quite sporadic, with completely normal functioning in the interim. The "peeling" either happens in time, or it doesn't. Maybe peeling is the wrong word. I imagine it probably pops back rather suddenly, more or less all at once. Kinda like breaking a form fit that is so perfect, it can be adhered, even without a molecular bond. But once it starts to give in one spot, the entire bond is gone quite fast.

Tuner was right on that one. I was barking up the wrong tree looking at pressure during extraction. It appears that it may be more a matter of how long after pressure has dropped before a given case can be reliably extracted.

 

[JRH6856]

I picture this: High peak pressure imprints the case to the chamber. Longer delay before extraction means more time for the case to "peel" away, even though pressure drops quite rapidly once the bullet leaves the muzzle. ?

That is how I understand it.

And if you are talking about reloads, consider the effect that work hardening has on the brass. Newer brass, being more malleable should have higher expansion and adhesion. The more it is fired and resized, the harder and more brittle it gets. It is more likely to split rather than expand and adhere.