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Hello everyone. I have a few questions regarding the general reliability of the Glock 10mm models such as the G20/29 when firing the Underwood/Buffalo Bore loadings or say hotter (non-nuclear) hand-loads.

My ideal functioning range of ballistic performance would be minimum 180 grains @ 1,200 FPS and ideally within the 1,300 FPS range.

I’ve read conflicting information regarding the functioning of the Glock 10mm, namely the slide potentially outrunning the magazine springs for example when using the UW/BB ammunition.

Aftermarket fully supported barrels, heavier recoil springs, stronger magazine springs, etc. I would rather not modify a carry gun just to shoot “real” 10mm.

From what I understand, a heavier recoil spring whilst slowing the reward travel of the reciprocating slide, it also generates more force going back into battery. A fully supported barrel concerns me in regards to the weapon cycling as reliably as the presumably looser tolerances of the Glock OEM barrel, not to mention going outside the factory specifications of the barrel lockup to slide fit.

I’m interested primarily in a pure 10mm carry gun, specifically the G29. I’m confident it will function 100% with factory Federal HST or Speer GoldDot 200 grain ammunition for example, I would prefer to use the Underwood 180 grain loaded GoldDot if the weapon will be reliable without any modification to the factory specs other than sights.

If any of you have any experience with the above I would love to pick your brain. Thank you.

Happy Thanksgiving and God Bless!
 

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I ccw a glock 20 my carry load is the underwood 180gr gold dot (although I just bought some of the new winchester silver tips in case underwood can't get those back in stock). I have shot everything from federal 40 s&w loads to the underwood offerings from the stock barrel and never had a single issue. This is with around 200 rounds of defense ammo and several thousand rounds of target ammo.

If you go this route I highly recommend the sig and magtech offerings for your range ammo as they are warm enough to accurately represent what the real stuff is like.
 

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I don't recall reading anything, here, about 10mm slides outrunning mag springs. If the slide is cycling, fully, it's doubtful it will out run a mag spring no matter what the spring rate is. A short stroke with an extra power spring could cause this but as said, I don't recall seeing those kinds of failures, here, with 10mm.
 

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Reliability of my 20 is thus far 100% but I've only shot jacketed bullets through it. Having said that, a month ago, I finally got some Underwood 220 gr cast and a KKM barrel to shoot heavy cast bullets and theoretically because the tighter match cut chamber might be easier on the brass... I haven't tried the 220's yet but keep intending to...
 

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PS, If your Glock 20 is a Gen 4 it has a dual recoil spring assembly. I think the Gen 3 and earlier have a guide rod with a single recoil spring. The Gen 4 dual spring assembly is supposedly stronger than the Gen 3 and earlier springs. This should affect how fast the slide opens and closes and advice on older G20's might not be applicable to the Gen 4.
 

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My Glock 20 has a KKM barrel and 20# RSA. I set it up this way to shoot 220 grain hard cast Buffalo Bore and also factory Hornady 180 XTPs. It’s been basically 100% for the last 11 years and many thousands of rounds. I was my last duty pistol before I retired from LE.
 

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Bone stock G29 here. An old one (no rail). It’s been 100% with quality ammo including DT, BB, UW, etc… No special springs or guide rods here. I actually CCW it. No concerns here. Great gun.
Weirdly I’ve had better reliability with the 29 and even a converted 30 than my 3 20’s over the years?

I’m no expert, but have been a little bit down the rabbit hole. My theory is that with hot loads people often go for the recoil spring first, when higher power magazine springs are more likely to be the fix. The gun sometimes seems to be cycling too fast for the round to come up from the mag to properly load, and so a higher power recoil spring just snaps the slide back even faster exacerbating the problem.

My own endgame was to accept that if I wanted a G20 to shoot 180 grain bullets at 1,000 to 1,250 FPS or so, stock typically worked fine (maybe stronger mag springs if a problem). If I wanted lighter bullets at big time fps or really pushing 180’s to the brink, then that was going to be a specialty setup not 100% with other loads.

YMMV
 

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I’m well past 70,000 rounds through my G20 over the past (almost) 20 years - and don’t recall a single feed issue. Not kidding…

FTF is most often caused by weak rounds not cycling the slide completely - not hot rounds cycling the slide too fast.

Glock reliability!

kestrou
 

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That or weak wrist/ limp wrist
My only failure to feeds with Glocks have been my powder puff reloads in subcompact, dual spring Glocks. The compact and full sized Glocks handle these weak loads fine but the dual recoil spring assemblies in the subcompact models seem to be too stiff for very weak ammo.

To answer the OP’s question. my G29 has been very reliable, even with my reloads.



Sent from my iPhone using Tapatalk Pro
 

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My gen 3 G20 worked fine with regular "weak" 10mm ammo with the stock rsa. No so much with Underwood coated hard cast 200 grain ammo. Changed out the stock spring for a heavier unit and now it works fine with everything.
 

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I’m one of those guys that has serious problems with the G20 and full power loads. I have three G20’s (gen2, gen3, gen3sf) a G29, and a G40. The G20 is the only one that has problems…and it’s systemic, it affects all of them. Full power for me is 200grains at 1200fps or more. The slide absolutely over-runs the next round in the mag., even with Wolff +10% mag springs. Extra power recoil springs make the problem worse. I picked up an aftermarket dual recoil spring that helps, but every once in a while it will still FTF. The only 100% solution is keep the rounds just under 1200fps. Neither the 29 or 40 have the problems. The G40 is not pleasant to carry but it’s an absolute joy to shoot. It eats anything and is not picky about ammo in terms of accuracy. It just shoots.

I’m looking forward to wringing out the new Smiths and see how they handle the full power stuff.
 

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I don't recall reading anything, here, about 10mm slides outrunning mag springs. If the slide is cycling, fully, it's doubtful it will out run a mag spring no matter what the spring rate is. A short stroke with an extra power spring could cause this but as said, I don't recall seeing those kinds of failures, here, with 10mm.
I've read before, but not experienced personally, that using very hot loads (grossly overpressured) will increase the slide velocity so much so that the action retracts and closes before it can strip a fresh round from the magazine which necessitates an extra power mag spring and/or a different recoil spring setup.

If it were me, I would shoot a few boxes through the OP's pistol with whatever ammo he was wanting and see it how ran stock before trying to tune it then if I still couldn't get it, I would ask myself was all the extra BS actually worth it and I would answer - no it is not.
 

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I’m one of those guys that has serious problems with the G20 and full power loads. I have three G20’s (gen2, gen3, gen3sf) a G29, and a G40. The G20 is the only one that has problems…and it’s systemic, it affects all of them. Full power for me is 200grains at 1200fps or more. The slide absolutely over-runs the next round in the mag., even with Wolff +10% mag springs. Extra power recoil springs make the problem worse. I picked up an aftermarket dual recoil spring that helps, but every once in a while it will still FTF. The only 100% solution is keep the rounds just under 1200fps. Neither the 29 or 40 have the problems. The G40 is not pleasant to carry but it’s an absolute joy to shoot. It eats anything and is not picky about ammo in terms of accuracy. It just shoots.

I’m looking forward to wringing out the new Smiths and see how they handle the full power stuff.
you just need to find a pleasant way to carry the G40
;)
 

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extra power mag spring and/or a different recoil spring setup.
will out run a mag spring no matter what the spring rate is. A short stroke with an extra power spring could cause this
I was a little vague in my first post. This spring I am talking about in red is the RSA. I get you know what I was saying but some others may not. ;)

I've never experienced it, either. Somehow never got the wrong combination, enough, to cause that phenom.
 

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It's always interesting some people have perfect running G20's and some don't when these 10mm threads come up. It seems like there's something about the length of the barrel/slide combo that just doesn't like ammo in the 240+ power factor range. Seems you can run a G22 with extra power ammo (180 gr at 1100 fps) and not have issues but getting the G20 to cycle 200gr at 1200 fps or 180gr at 1350 fps isn't foolproof. That's quite a bit of PF to ask from a polymer 10mm with a slide that isn't all that heavy.

FWIW, a lower power factor ammo that functions 100% is a better than the hot stuff that isn't completely reliable, IMO. I'd rather have a triple tap on a bear or moose with quality 10mm ammo verses the cannon stuff that may choke, for whatever reason, after the first shot. YtoohotammomakesyouagoodchewtoyMMV
 

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Hello everyone. I have a few questions regarding the general reliability of the Glock 10mm models such as the G20/29 when firing the Underwood/Buffalo Bore loadings or say hotter (non-nuclear) hand-loads.

My ideal functioning range of ballistic performance would be minimum 180 grains @ 1,200 FPS and ideally within the 1,300 FPS range.

I’ve read conflicting information regarding the functioning of the Glock 10mm, namely the slide potentially outrunning the magazine springs for example when using the UW/BB ammunition.

Aftermarket fully supported barrels, heavier recoil springs, stronger magazine springs, etc. I would rather not modify a carry gun just to shoot “real” 10mm.

From what I understand, a heavier recoil spring whilst slowing the reward travel of the reciprocating slide, it also generates more force going back into battery. A fully supported barrel concerns me in regards to the weapon cycling as reliably as the presumably looser tolerances of the Glock OEM barrel, not to mention going outside the factory specifications of the barrel lockup to slide fit.

I’m interested primarily in a pure 10mm carry gun, specifically the G29. I’m confident it will function 100% with factory Federal HST or Speer GoldDot 200 grain ammunition for example, I would prefer to use the Underwood 180 grain loaded GoldDot if the weapon will be reliable without any modification to the factory specs other than sights.

If any of you have any experience with the above I would love to pick your brain. Thank you.

Happy Thanksgiving and God Bless!
I have Glock 20SF that I bought in 2013 and fired with several types of 10mm ammo including Winchester silvertip 175 grain ammo Blazer 200 grain ammo, PMC180 grain. S&B 180 grain and Underwood 180 grain XTP ammo. I also fired tow 50 round boxes of 180 grain 40 S&W to see if there was any difference in accuracy or reliability and there was no difference in either accuracy or reliability. All ammo fed flawlessly out of the factory barrel end using the factory 17 pound recoil spring and the frame has showed no signs of battering with the standard factory weight spring and full poer ammo..

Then I got a six inch Lone Wolf barrel and a Lone wolf stainless steel guide rod but with the factory weight 17 pound spring which proved adequate with many more rounds of Underwood ammo including 180 grain XTP and dot, 200 grain XTP, and 200 and 220 grain hardcast. After a while, I decided that I didn't like the 6 inch barrel and cut it down to 5 inches so that it only stuck out a half inch beyond the slide and balanced better and was faster to get out of the holster and on target for use as a woods gun in bear country.

Most commercial 10mm ammo is under-loaded and I suspect that it's loaded to the same pressure levels as the 9mm and 40 S&W which is 35,500 psi whereas Underwood Double Tap and Buffalo Bore ammo is loaded to the same 37,500 psi as the original Norma loads. At the time, the Winchester Silvertips seemed to be the hottest ammo in the 175-180 grain weight rand and was rated at 1290 fps but only chronographed at 1100 fps out of my gun while the Underwood 180 grain ammo chronographed at an average of 1290 fps. I suspect that the Winchester Silvertips 1290 fps was achieved with a test barrel longer than the 4.6 inch barrel of the Glock 20.

The only problems I ever had with this gun has been with the Lone Wolf barrel and the Underwood ammo Underwood uses its own brass and I think it's may be thicker than standard brass and won't always pass a "Plunk Test" where a round will not drop freely into the lone wolf chamber of the barrel of the gun that has been removed from the gun which in the LW barrel, is tighter than a Glock factory chamber, So what I did after I got the Lone Wolf barrel and had it polished, I would do a plunk test with every 20 round box of ammo that I bought, and usually ony 1 or 2 round would be a tight fit and I would set those rounds aside for practice ammo.

And as I said,I only had this problem with an aftermarket barrel and NOT with the Glock factory barrel.
 
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