UGH-- So much recoil spring misinformation!

[Hohn]

So I've been researching recoil spring options for my new G20, and in that research I've found one thing that sticks in my craw: some absolutely absurd explanations for the effects of changing "spring weight" (I'll explain the quotes in a minute).

I'm guessing the overwhelming majority of INGOers already know this, so please pardon my having to vent.


Consider this from "Custom Glock":

UPDATE:
We just received the new ISMI 11 pound recoil springs. These should eliminate or greatly reduce the need for cutting 13s. I have not done extensive testing yet but they should work great in the 9mm guns and the compacts.


Effects of a lighter spring:

Recoil is transferred to the shooter in a shorter duration of time because the slide is moving at a higher velocity. This is often perceived as less recoil and reduced muzzle flip.

With a lighter spring the shooter also has less force to counteract, or you don’t have to work as hard. This usually reduces muzzle flip.

Less force to counteract reduces the odds of producing a limp wrist style jam.

A lighter spring will result is reduced muzzle dip when the slide closes keeping sights steadier and on target for a faster follow-up shot.

Light springs are particularly helpful to smaller shooters like children, women or anyone else having trouble keeping their wrists locked.


Effects of a Heavier spring:

Recoil is transferred to the shooter over a longer duration of time due to lower slide velocities.

Slower slides equal a longer recovery time for the shooter.

The shooter does more work, as there is more force to counteract. This often causes and increase in muzzle flip.

The chances of a limp wrist style jam are increased, as there is more force working to unlock your wrists.

The chance of the slide short stroking and causing a feed jam is increased.

Increased muzzle dip when the slide closes for a slower follow-up shot.

Let's begin with an important clarification related to the quotation marks I used in "spring weight." The force a spring exerts is not a function of its "weight", but a function of its RATE.

You can produce identical spring *rates* with very different weight springs. For a given rate, a coil spring can either have heavier wire and more turns per inch, or thinner wire with the turns farther apart. They will have different fatigue properties and other spring considerations (set height, solid height, etc), but they can be made to have the same *rate* within a range.

Let's also establish up front that the "perfect" recoil spring only exists for a given load. Even with identical charges, going up or down in bullet weight will change the "ideal" spring rate.

So the above statement that a shooter "does more work" with a stiffer recoil spring is absolutely bogus. The shooter will not "do more work" either in a practical sense or in the sense of physics. Unless the spring is so stiff that it won't allow full slide travel (potentially causing FTF), the shooter does the same amount of work. Either the shooter has to resist the reaction force of the spring compression, or he must resist the inertia of the slide once the spring is fully compressed.

The lighter the spring, the less energy it stores, leaving more impact energy to the shooter's hands once the slide is fully retracted. A heavier spring stores more energy, so there is less kinetic energy sent to the shooter's hand when the slide is fully retracted (but marginally more force sent WHILE the spring is compressing).

We can see now why the "more muzzle flip from a heavier spring" is also false. Muzzle flip comes not from the relatively small force to compress the spring, but from the huge impact when the slide fully retracts.

This is plainly visible in this video. When does the muzzle rise the fastest? When the slide smacks the stops:

http://youtu.be/ysp3XHxT9mk

So a heavier spring will not cause more muzzle flip. It will reduce it.

Does it reduce recoil? No. There's still a reaction force-- Newton's law of equal and opposite reaction is a "law" for a reason.

But the perception of recoil can be manipulated to produce a higher *average* recoil force in exchange for a smaller *instantaneous* recoil force. However, the total area under the curve will always be the same.

 

[Vince49]

OK

Precisely. So why do you wish to replace the stock RSA?

 

[Rob377]

There's a whole bunch of misinformation in this thread all right.

 

[Hohn]

Precisely. So why do you wish to replace the stock RSA?

I'm not sure I do. I'd read that a lot of people are doing so-- going up, down, etc.

So I figured I'd survey the landscape and then make up my mind.

I was intrigued by this video showing consistently that the heavier spring in a G20 reduced variation and slightly increased velocity with hotter 10mm loads (like underwood).

Worth the time if you have a minute:

http://youtu.be/lkz492WFtkM



There's also some commentary from Buffalo Bore that makes a reasonable point that stronger ammo needs a stronger spring to avoid premature breech opening:

If you are firing this 10mm ammo from an autoloader and experience high extreme spreads in velocity, it is not the ammo. Here is why and how to remedy the situation.
Full power 10mm ammo has always generated enough recoil and pressure to require a pretty stiff recoil spring in your handgun - this of course depends on several variables such as your slide weight, etc. When the cartridge fires, it generates enough pressure/recoil to prematurely open your breech face in some guns. When this happens, the opening breech face has an effect on the burn rate of the powder. This can result in some fairly high extreme spreads in velocity. If you are experiencing extreme velocity spreads of more than 50 fps, simply install a stiffer recoil spring. For example, I have an original Colt Delta Elite. This gun with the factory spring runs extreme spreads of about 35fps with both of these 10mm loads. I am happy with 35 fps, so I leave the Delta Elite as is. I also have a custom built Para Ordinance with a Nowlin barrel. It runs extreme spreads of about 70 fps with its original recoil spring. When I install a spring that is 4 lbs stiffer, the extreme spread drops to about 35 fps. The new Glock model 20 comes with a recoil spring that allows the breech face to open too soon and my new Glock model 20 will get extreme spreads of about 100fps with the factory spring installed. When I go to a stiffer recoil spring, the extreme spreads drop to about 50 fps in my new Glock model 20

Does the increase in ES matter? Probably not. I doubt in the real world anyone would notice it at all.

 

[Hohn]

Here's a video that shows the phenomenon using a 1911 in a Ransom rest:

http://youtu.be/F506XIMEz0M


What are seeing there? Note that the slide goes to the rear and parks there for an instant. See that?

That brief stoppage of the slide is really important. If the slide doesn't stop long enough before it moves forward, the mag can't feed a round up fast enough and you'll have a FTF when the slide won't strip a round from the mag.

But more than than means that the shooter is acting as the recoil spring. The stoppage of the slide represents recoil impulse transmitted to the shooter as a spike in force.

Aside from the videos showing the full slide retraction is the peak of muzzle flip, we also know logically that this must be true because until the slide is fully retracted, there is always some available spring travel that must be overcome before the slide's momentum can act directly on the frame.


The pros that drop down spring tension are also running much lighter loads-- which makes sense. The spring needs to match (as best it can) the intensity of the loads used.

jmo

 

[netlander10]

I realize this thread started out with glocks, then brought in 1911s. I don't know glocks. But the 1911 is a toggle link design, too light a spring doesn't allow for enough dwell in the barrel link that connects the barrel to the slide stop pin. That can and will cause nasty side effects. It can peen off the edges of the barrel locking lugs and do the same to the locking lugs in the slide hood. Even worse the frame ha a much higher risk of cracking. Usually above the slide stop pin hole. None of these are cheap repairs. Its not worth messing around with for the average shooter.
If you have to experiment in this area use those little shock buff frame savers. Check it often and they are getting chewed up every 50 rounds or so go to a heavier spring. I learned that from one of Wilson's gunsmiths.

 

[Double T]

I realize this thread started out with glocks, then brought in 1911s. I don't know glocks. But the 1911 is a toggle link design, too light a spring doesn't allow for enough dwell in the barrel link that connects the barrel to the slide stop pin. That can and will cause nasty side effects. It can peen off the edges of the barrel locking lugs and do the same to the locking lugs in the slide hood. Even worse the frame ha a much higher risk of cracking. Usually above the slide stop pin hole. None of these are cheap repairs. Its not worth messing around with for the average shooter.
If you have to experiment in this area use those little shock buff frame savers. Check it often and they are getting chewed up every 50 rounds or so go to a heavier spring. I learned that from one of Wilson's gunsmiths.

Did he sell you some buffers as well? Must've been some great misinformation.

Use the factory recommended spring weight for factory ammo. If you are loading "light" loads, then you need a lighter spring for the slide to go rearwards enough to eject and strip a round.

A magazine doesn't move a round "up" until it is stripped and the breach is closed. Not having enough time for the magspring to raise a round is a non-issue. You may have issues with slide stops not catching though.

 

[SERparacord]

5" Government models are equipped with an 16.5# recoil spring as standard , while the 18# recoil spring is generally preferred for heavier loads. YMMV

 

[HoughMade]

First time I ever saw anyone claim that the same force over a shorter period of time = LESS felt recoil.

 

[netlander10]

Nope, I use the shock buffs when working up handloads. I loaded .400 carbon and 9x23. They have different recoil impulses than .45. Just my 2 ct. from 31 years with 1911s

 

[koutsevil]

I upgraded my Glock 26 with a tungsten recoil assembly. I got the same rate spring as stock. It definitely tamed the gun. The muzzle doesn't flip up as bad as with the stock assembly.