I recently purchased a Glock 20 10mm. A couple of the ammo makers advise getting a stiffer/heavier spring in order to reduce extreme spread of velocity. Anyone have experience with this and would like to comment? The ammo I like the most is DoubleTap 200gr JHP@ 1200fps. It shoots remarkably well in the 4.6" barrel. I just got a 6" hunting barrel from Glock and my "friend" says I'll need a heavier spring for that application.

What say ye?

Andy

As cheap as Glock springs are, I'd probably just buy a heavier spring to see if it made any difference. That said, at the ranges a Glock would be shot at, I doubt you'd see any differences on paper between the two springs even if the extreme spreads were different.

Unless some else can tell me why the recoil spring would have anything to do with bullet velocity.

I don't think it well, silde velocity yes bullet velocity no. The bullet is out of the barrel before the barrel unlocks.

The recoil spring well not have any effect on bullet Velocity.

A heaveier spring will help keep your pistol from being beaten to death but no effect on bullet velocity.

From the folks at Buffalo Bore in reference to their 200gr FMJ@1200fps

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. Of course none of this will be an issue in a revolver. None of this will be an issue in real life either, as these high extreme spreads don't hurt accuracy or function. However, I mention this because if you are like me and want things to be as correct as possible, I have outlined the problem and the solution. The industry fixed all these problems initially, by watering down the 10mm ammo over the last several years. The watered down 10mm ammo does not generate the pressure/recoil to open the breech face early. If you want the full powered 10mm ammo we make, you simply need to tweak your pistol. Or just realize that you are getting some fairly high extreme spreads and ignore it or live with it.

quote:

When the cartridge fires, it generates enough pressure/recoil to prematurely open your breech face in some guns.

I guess I just don't understand this statement at all if they mean that this phemonenon is unique to the 10mm. Having said that, I do have a heavier spring in my 10 mm. My accuracy load happens to be close to max ie. 200 gr. bullet at just over 1200 fps. and it is accurate. I am not sure that I would notice any affect on accuracy at 25 or 50 yards without a HUGE extreme spread. I also use a heavier spring in my 45 acp., 38 Super and 9x21 Major loads, for the reason noted above, ie. I don't want the gun beating itself to death.
Peter.

I agree with Tim Sundles of Buffalo Bore on the above 100%.

It is not just with the 10mm but it can occur with any very powerful loads shot in a semiauto handgun.

Once upon a time I loaded the 1911 in 45 ACP, "way up there" [before I know better, as the movie line goes].

I not only used a 28lb recoil spring, and a recoil reducer built into the recoil spring guiderod, but I also used an increased power hammer spring.

All of these things were designed to;
Retard the slide opening,
Slow the cyclic rate/slide velocity,
And limit the battering of the frame/recoil shield on the slide.

Everything worked great, till I broke the feet off the barrel bushing, which launched the recoil spring and recoil spring plug out the front of the gun...

A beefed up bushing cured that problem.

The main issue with a heavier spring is you cannot limp wrist the gun, and it might not function with lower power loads.