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Serious recoil springs for serious recoil.

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You guys apparently do not have good reading comprehension. I clearly stated that it was not a 10mm chambering. I will not discuss the chambering associated with this project, since that is not up for discussion at this time.

I can appreciate concerns regarding the fear of my breaking a critical part of my gun. However, please do not post such comments unless you have factual knowledge of such issues, otherwise it is unproven speculation.

______________________________________________________________________________________

Please do not respond to this thread unless you have a real idea where I can find a recoil spring system for a gun that can handle dramatic recoil impact.

Thank you.

So far, what I have found is a recoil system produced by a Greek manufacturer called DPM. They do manufacture a spring kit for the Glock autopistol that appears to have a progressive rate. I have contacted the manufacturer today, but since it is a Saturday I do not expect a response back from them until Monday at the earliest. The system looks promising as it has been carefully designed around the action of the pistol. The progressive rate springs (3 in total) may have enough resistance to counter the force I expect will be present, but since these spring sets are not off-the-shelf parts here in the U.S., I will have to wait until their response or if they do not know, perhaps order one and try it out first. Upon initial observation, I am impressed by the design.

Jeff Quinn has given some interesting hints regarding the design of this recoil system here in case you are interesting:

http://www.gunblast.com/DPM.htm
 
OK, so it won't be a 10mm round you're shooting. But the need for a 40 lb spring implies that you're looking at something hellacious such as a .50AE or bigger handgun round. Are you sure that the frame is going to be able to stand up to something of that magnitude?

Also I'm curious what led to the calculations of a rate of 40lbs per inch on the spring. for most common handgun cartridges varies from a low that I know of at 11lbs for my CZ's when running minimal power factor ammo for IPSC to the 23 lb maximum available for your Glock 10mm. The need for a 40 lb spring implies something up into the .45Automag or 50AE and more powerful rounds. Rounds that would not even fit into a magazine that will go into a Glock grip frame.

If it's a big secret I don't really expect an answer but you've certainly got the curiosity gland pumping now.... :D
 
It is not going to be 50AE power...but it's probably going to feel like the equivalent of a .45/70 chambered in a Desert eagle, from an energy to size of frame ratio perspective.

The gun will handle it - particularly if the recoil system is designed correctly. This would probably not work on a stock Glock pistol. Mine is not stock. ;)

The new chambering (again, I am not disclosing/discussing this part) will be a load work up, but based on how other springs function (I have a stock recoil spring, 21#, and 23# spring kits for my pistol) relative to various loads, I'm "estimating" what I expect the recoil will need in terms of spring rates.

I may wind up designing an adjustable rate recoil spring set for this gun if I can't find any systems out there like what I'm envisioning.
 
The entire thread is based on the erroneous assumption that a heavier recoil spring reduces felt recoil. This is a common misconception, but a misconception nonetheless.

A heavier recoil spring actually increases the force applied to the hand, wrist, and forearm, and therefore, has the actual effect of increasing recoil.

That is not to say that a heavier recoil spring can't have some advantages in the shooting characteristics of your pistol. It does increase the recoil impulse, which has the effect of making recoil less snappy, and can seem to smooth things out. My Glock 20 with the factory 17# spring had a tendency to jerk around a little bit. I tried the 20 and 22# springs in it and settled on the 20# spring simply because it kept brass reasonably close, smoothed things out a little, and made it slightly less snappy, but didn't increase the recoil quite as much as the 22# spring. I generally try to keep the lightest recoil spring possible, but stepping up to the 20# was deemed acceptable for me given the circumstances.

Acknowledging that the OP isn't using a 10mm Auto, it still has to be something that can fit in a .45/10mm grip, and I still have a tendency to believe the #40 spring is excessive, especially under the mistaken premise that it is going to reduce recoil.
 
you can buy springs, wolf either buys or makes springs in convenient sizes for guns, the matter is finding a heavy spring in the appropriate size. Start looking at spring makers or buy piano wire and learn to make your own.
 
woodsman some of use do release your pet ain't a 10mm but the working pressure or the same as what your talking about and the same base platform to start with. Just 300fps faster. Keep your insurance up ,you may need it.
 
I just can't wrap my head around why you would want to put that powerful of a round out of a plastic pistol. Call me close minded but you couldn't pay me to be the first to shoot that thing.
 
http://www.brownells.com/.aspx/pid=40143/Product/_3174_HOW_TO_MAKE_FLAT_AND_COIL_SPRINGS

There you go. Buy some different gauge wire and have fun. If your smith is competent enough to SAFELY rechamber a barrel, modify the feed ramp , magazines, etc. making a spring should not be a problem. I'm hoping you own a Ransom Rest because I wouldn't want to be holding a gun chambered in whatever wildcat you are thinking about shoving down the pipe.
 
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I already promised I would produce a video of this with my firing the hottest loads I am able to stand with it.


BLUEYES: Thank you.
 
You obviously don't know what you're talking about. I'll tell you why I say that:

Once you work up 10mm loads to approximately the max SAAMI pressure for that cartridge, the 20# spring will no longer work in your pistol. The pistol will fire the first round, it will fail to extract the brass and then another round will get caught between the slide and the spent primer of the fired brass. Increase the rate of recoil to match the action of the pistol under higher pressure of the cartridge and the pistol will function properly once again. If it was just a matter of the "feel" of the pistol, I wouldn't have bothered buying additional rate springs - and certainly I wouldn't be requesting help on finding higher rate spring sets for this gun.

The thread is based on a very real-world presumption that every action has a reaction and in this case, it's the action of the power of the cartridge throwing the slide backward on the frame, ejecting, extracting and picking up another round out of the magazine.

If you think you can run a 1100 fpe cartridge through a pistol designed for a 700 fpe energy cartridge, recoil energy of those being somewhat on the principle of proportional relationship to the muzzle energy, you obviously have a few things to learn about the mechanics of a modern semi=auto pistol action.

AGAIN, I would appreciate it if you don't have something concrete to offer in the discussion, please do not reply to it.

The topic here is that I am looking for a set of 40# springs for a Glock G29. If anyone can help in this quest, I would appreciate it.

Thanks!


The entire thread is based on the erroneous assumption that a heavier recoil spring reduces felt recoil. This is a common misconception, but a misconception nonetheless.

A heavier recoil spring actually increases the force applied to the hand, wrist, and forearm, and therefore, has the actual effect of increasing recoil.

That is not to say that a heavier recoil spring can't have some advantages in the shooting characteristics of your pistol. It does increase the recoil impulse, which has the effect of making recoil less snappy, and can seem to smooth things out. My Glock 20 with the factory 17# spring had a tendency to jerk around a little bit. I tried the 20 and 22# springs in it and settled on the 20# spring simply because it kept brass reasonably close, smoothed things out a little, and made it slightly less snappy, but didn't increase the recoil quite as much as the 22# spring. I generally try to keep the lightest recoil spring possible, but stepping up to the 20# was deemed acceptable for me given the circumstances.

Acknowledging that the OP isn't using a 10mm Auto, it still has to be something that can fit in a .45/10mm grip, and I still have a tendency to believe the #40 spring is excessive, especially under the mistaken premise that it is going to reduce recoil.
Click to expand...
 
You obviously don't know what you're talking about.
Click to expand...

Well...Yes he does, actually.

This is gonna be a little long, so grab a cuppa Joe and settle in.

Recoil in an autopistol is a little different than it is in a fixed-breech weapon...like a revolver.

With the revolver, the recoil impetus is transferred directly to the recoil shield, and hence the frame. It doesn't work quite like that with a self-shucker.

With the autopistol, the "gun" is comprised of the barrel and breechblock...the slide. The frame is essentially no more than a gun mount...and it moves on a rail with no solid connection between the gun and the mount. The only connection is the spring. If the gun has a hammer, the mainspring also figures in.

Because the recoil system is basically a closed system, when it starts moving, it sets up an action/reaction event that's separate and apart from the ballistic event that caused it to start moving.

The sides of the event are the spring and frame. The force vector is provided by the spring. When the slide starts to move, it compresses the spring, and the spring exerts its force on the slide and the frame...pushing the frame rearward as it exerts a forward push on the slide. The stronger the spring, the more force it exerts.

Here's where it gets interesting.

By the time you actually start to detect recoil with a locked breech autopistol...the ballistic recoil is over...because the slide only moves a short distance before the bullet exits. About 1/10th inch nominally. The recoil/action spring hasn't compressed enough to exert much force above what it took to set it into motion against its static, preloaded state. With a 16-pound spring...that's about 7 or 8 pounds. You get a little push, but it's being absorbed by the spring.

As the spring compresses farther, the force that it exerts rises...but you still don't detect a lot of felt recoil until the slide impacts the frame...which is where about 90% of what we know as muzzle flip occurs. Impact causes it...not recoil.

If we increase the load and rate of the recoil/action spring, the force of the spring is transmitted at a faster rate. It becomes sharper, and starts to behave more like a fixed-breech pistol. It's theoretically possible to find a spring so strong that the slide can't move at all, and thus becomes a more "solid" connection between slide and frame...and then the autopistol's recoil will be exactly like the revolver's.

It may be a little easier to understand if we hypothetically place springs on the butt of a bolt-action rifle, between the end of the stock and the buttplate, and firing it side-by-side with an identical rifle equipped with a standard stock. The modified rifle's recoil will be softer, because much of its energy is being absorbed over a longer time frame by the spring. It becomes more like a push than a punch.

Back the autopistol.

Hypothetical gun, with 30-foot frame rails. The slide is mounted way out on the front.
There is no recoil spring. To minimize friction, let's use ball bearings between the frame and slide rails. Let's also fire the gun electronically in order to eliminate any connection between gun and mount, other than the rails. The impact abutment that stops the slide is way back at the rear, so the slide has to travel 30 feet in order to reach it. Aside from these things, the gun operates normally...linking the barrel down at 1/10th inch of slide travel.

You could fire that gun and never feel a thing in the way of recoil, unless and until the slide hit the frame.

Cheers!
 
Am I going to have to show the math?
Click to expand...

Go for it...then I'll see if I can dig up that slow-motion video that shows the gun barely moving until the slide hits the frame.

Meanwhile, just for giggles...Here's an old fluroscope photo of a 1911 during the firing sequence.
The base of the bullet is about an inch from the muzzle, and by noting the position of the link...it appears that the slide has moved approximately .075-.080 inch.

Of you look closely, you can see the bones in the shooter's hand. Take note that the muzzle hasn't rolled upward in recoil to any signifigant degree, and the gun appears to be relatively undisturbed.

By applying some pretty simple math, you'll find that by the time the slide impacts the frame, the bullet...moving at a nominal 830 fps...will probably be 20 yards downrange before the muzzle flip that we recognize as felt recoil occurs.

Gun20Fired.jpg
 
1911Tuner said:
If we increase the load and rate of the recoil/action spring, the force of the spring is transmitted at a faster rate. It becomes sharper, and starts to behave more like a fixed-breech pistol. It's theoretically possible to find a spring so strong that the slide can't move at all, and thus becomes a more "solid" connection between slide and frame...and then the autopistol's recoil will be exactly like the revolver's.
Click to expand...
This is a better explanation - and less facetious ;) - of what I was trying to get at in my earlier post. And surely it would be nearly impossible to hand rack the slide to chamber a round.
 
The ideal spring weight for a given load will be the one that absorbs most of the recoil before the slide impacts the frame in rearward movement, but that still is absorbing recoil almost to the end.

What that will do is transmit the recoil impulse over the longest period of time, giving the lowest possible perceived recoil and muzzle flip while reliably cycling the round.
Too light and the slide opens sooner, slams rearward with more force, generating significant perceived recoil and muzzle flip, and battering the gun.
Too hard and most of the recoil energy is absorbed in the beginning, transmitting most of the recoil to the frame much faster, generating more muzzle flip and perceived recoil. Obviously too extreme and the gun wouldn't even cycle.

Stronger loads can benefit from stronger springs, but with recoil it is typically momentum and not energy that should be factored.
Since the recoil impulse is not acting on the spring directly, but must first counter the weight of the slide the slide weight also is a major factor.


Doing a quick search and stealing some data from a momentum chart someone else posted online:

10mm Auto, 155 gr @ 1410 fps, Momentum = 31.2 lb-f/s - Muzzle Energy = 684 ft lbs
10mm Auto, 180 gr @ 1240 fps, Momentum = 31.9 lb-f/s - Muzzle Energy = 615 ft lbs
10mm Auto, 200 gr @ 1050 fps, Momentum = 32.9 lb-f/s - Muzzle Energy = 587 ft lbs

As you can see the momentum is often greatest in heavier bullet loadings and rounds with greater energy can actually have less momentum.
In the 10mm auto loads listed in fact the momentum was least in the higher energy loads, and the heaviest projectile loads had more momentum.
This is because the formula for energy significantly favors velocity over mass increases. While for momentum they are equal. So for loads operating around the same pressure and diameter, lighter bullet weights will have more energy and less momentum.
However for recoil purposes (and even terminal ballistics in my opinion for most handguns, but that is another topic) it is momentum that matters not energy.

Assuming a 20 pound spring would work great with the above loads (not sure what gun was used and so exact slide weight) that are generating over 31 pounds of momentum, it seems obvious a spring about 10-11 pounds less than the generated momentum would be good in that gun with its barrel and slide weight.
It is probably a Glock 20, which would give a known slide weight, but could be something else for all I know.
But for the gun in that table if a load was created that safely generated say 40 pounds of momentum in another caliber with a similar weight barrel and same weight slide, a spring around 29 pounds would probably function similarly.

(Now springs can get a lot more complicated, as compression rates can be linear or progressive, and other criteria must be factored in. But assuming it is made to operate within the firearm traveling the same distance, the above generalization should be a decent starting point.)


If you think you can run a 1100 fpe cartridge through a pistol designed for a 700 fpe energy cartridge, recoil energy of those being somewhat on the principle of proportional relationship to the muzzle energy, you obviously have a few things to learn about the mechanics of a modern semi=auto pistol action.
Click to expand...

Energy of the cartridge as I explained is far less important than the momentum of the cartridge in how much it will beat on the semi-auto pistol. Really light fast rounds can get some impressive energy figures while having low amounts of momentum. Likewise a really slow heavy round can have low energy figures and significantly more momentum.
Assuming you stay within safe pressure limits of the barrel and breech (and brass) being used, the momentum figure the firearm is designed to operate with is a better criteria of how well it will hold up to another load. It could be much higher energy, but if it has similar momentum it should be fine.

For example an 881 foot pound 9x25 Dillon (neat necked down 10mm auto cartridge) load of 90 grains @ 2,100 f/s would only have 27 pounds of momentum.
While the above 587 foot pound 10mm load of 200 grains @ 1050 f/s would have 32.9 pounds of momentum.
The result is the load with 294 foot pounds less energy would actually apply more stress to the frame of the firearm because it has 5.9 pounds more momentum.

Foot pounds of energy in handgun calibers is also generally a really poor measurement of power or terminal performance. Momentum is generally far more accurate in predicting results until you get into velocities higher than most pistols.



Assuming the pistol needs a spring around 10 pounds lighter than the momentum generated for the given slide wieght, and you need a 40 pound spring, that means the load you plan in the Glock 29 should generate over 50 pounds of momentum.
Even a 200 grain 10mm load at 1200 FPS only generates just over 34 pounds of momentum.
Even if what you are planning is safe in the barrel of another caliber, 50 pounds of force will batter the firearm far more than the loads the frame was designed for. .44 Magnum loads generate less than 50 pounds of momentum, and I wouldn't want to fire them on a Glock frame.
The piece of reinforced plastic the spring will be pushing all those pounds into within the frame may give out on you or at least experience excessive wear or dig into and strip off the polymer.
 
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The ideal spring weight for a given load will be the one that absorbs most of the recoil before the slide impacts the frame in rearward movement
Click to expand...

Find that ideal spring, and you'll need a lot of hand strength to manually operate the slide. You may also find that you often get short recoil-induced malfunctions. Aside from having to manually ready the pistol for succeeding shots, it operated normally and without damage.

Too light and the slide opens sooner,
Click to expand...

That's true with a blowback pistol, but not with a locked breech/recoil operated design.
The recoil spring has very little to do with slide delay. It has the least effect of any of the delaying factors. Pistolsmith Ned Christiansen proved that several years ago when he fired a 10mm 1911 repeatedly with full-power ammunition...without a recoil spring.

The recoil spring's primary function is stripping and feeding another round, and returning the gun to battery...not buffering slide impact. That it does do that is incidental.
 
Seems like this is the problem The woodsman is trying to solve:

The woodsman said:
Once you work up 10mm loads to approximately the max SAAMI pressure for that cartridge, the 20# spring will no longer work in your pistol. The pistol will fire the first round, it will fail to extract the brass and then another round will get caught between the slide and the spent primer of the fired brass. Increase the rate of recoil to match the action of the pistol under higher pressure of the cartridge and the pistol will function properly once again.
Click to expand...

Can such a malfunction ever be attributed to recoil spring rate? I've read many explanations for a failure-to-extract problem like that, but none of them ever mentioned springs as a culprit.

I've read of over-gassed auto-loading rifles not letting pressure fall far enough before extraction and the brass sticking in the chamber which causes the extractor to rip through the rim.

But I've never heard of that happened with a straight-walled pistol case.
 
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