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HomeHomeDiscussionsDiscussionsFirearms and Sk...Firearms and Sk...Glock 20 10mm Gen 4Glock 20 10mm Gen 4
New Post
12/30/2015 6:48 PM

So I've read on the interwebs that some people are experiencing FTF and feeding issues with Gen 4 Glock 20's.  Might be a real issue, or it just might be a few lemons here and there.  I am about to pick one of these up...would love some feedback from owners.  Anyone here carrying a Gen 4 10mm? I'll be shooting/carrying heavier loads, most likely hard-cast from Double Tap or Underwood.  Any feedback regarding reliability, or otherwise, is appreciated.

New Post
12/30/2015 7:04 PM

I've owned a Gen 4 G20 for a few years. Mine runs fine with Underwood 200 grain XTPs and FMJs. Also likes the American Eagle 180 and the weak Privi 180s. No issues with mine and it's what I took to Alaska in 2013 to carry when fishing. Mine probably has a little north of 1600 assorted rounds of the above through it with no major hiccups.

New Post
1/1/2016 8:57 AM
I have a Glock 20 Gen 4 and use it to carry when backpacking. I've only put about 100-150 rds through it but still feel pretty confident with it as I've trained a lot with with 9mm and .40 S&W Glocks.

Re: reliability. It hates Buffalo Bore hardcast 220gr loads. FTF about every other round. Too bad for me as I bought a bunch while the Glock was on order. Switched to Cor Bon 200gr FMJ over a hard cast core as a woods load. It is 100% with these as well as PMC 200gr, FMJ, Sig 180 gr FMJ, 180gr FMJ reloads and a few 175 gr Critical Duty rounds.
New Post
1/1/2016 9:37 PM
I just bought a G20 Gen 4 a couple of months ago and only have a couple hundred rounds through it, but so far it's been fine.

From my trips through the interwebs, I don't feel like there's a systemic issue with these guns. The 220 Hardcast has been a known issue for a long time, that bullet is a pretty wide flat nose, and has to be seated pretty far out to keep pressures low at the velocity it's running. That combination doesn't work in many guns.

I think you'd be fine with the 200 grain hardcast load. That's still a pretty high sectional density and will bust through just about anything you'd care to shoot.

Also there's some pretty dubious 10mm ammo, and some even more dubious hand loading data. I owned both a G20 Gen 2 and Gen 3 before this. I put thousands of rounds through both those guns and found they functioned really well with loads in the mid 600 to 700 ft/lbs range, but there are people trying to load it hotter than that and having issues.

The Gen 4 recoil system makes a noticeable difference in felt recoil.

It's a great trail pistol, as has been discussed elsewhere on this forum. I actually found this forum doing 10mm research.


New Post
1/2/2016 4:02 PM
Thanks for the helpful info guys. A Gen 4 20 followed me home today. I got some various fmj to try out, as well as some Hornady 180gr XTP's. I have some Underwood 200gr hardcast on order. Once I trust reliability, I am excited to add this to my Kit Bag rotation.
New Post
1/3/2016 7:27 AM
Also, I'm a bit confused on something. Will the stock gen 4 springs run 200gr hardcasts reliably, or do I need heavier springs? Regarding the barrel, is the stock barrel good to go for hardcasts? I clean my guns after each range session... Once I confirm reliability /accuracy, I don't see myself shooting hardcasts frequently. I hate to buy an aftermarket barrel if it isn't necessary, but if it is, it is.
New Post
1/3/2016 9:17 AM

First, I mispoke earlier about energy levels. What I should have said is the gun is fine in the low to mid 600 ft/lb area. It's when things get up to the 700 ft/lb area that some people report problems in some guns. Other folks are fine. Sorry bout that, my daddy brain was kicking in during the late night internet posting.

As far as the 200 grain hardcasts go, I'd just try them. If the Underwoods don't run for you, try some Double Tap. They aren't loaded as hot, but still get about 32" of penetration in ballistics gel. I'd shoot some, check the barrel for lead every so often, and see if the gun will feed them.

Those 180 grain Hornaady's you picked up are the path of least resistance, as far as getting a new G20 up and running quickly. They are accurate, reliable and widely available. Some folks will deride them as being "watered down." While it's true they don't meet the original "Norma Spec," the original Norma ammo didn't either. The Hornady 180 XTP runs about 1170 FPS over my chronograph, right at the advertised velocity. That works out to 583 Ft/lbs of energy, which is right around a "warmisih" .357 load. It penetrates 16" to 18" inches of gel.

I think that load is fine for anywhere in the lower 48 where there aren't Grizzlies, so I'm carrying it for now. I'm doing to sort out some 200 grain loads gradually, and will likely switch over to a 200 grain load for a little extra oomph.
New Post
1/3/2016 2:24 PM
Wose, thank you. That last post is very helpful. I'll make sure the XTP's run well and get the 20 out for some miles. I'll work with the Underwood hardcasts and see what happens. Hoping they run well. I'm sure the XTP's are sufficient, but it'd be nice to know I had the extra punch available if needed for large animals. I got charged by an angry female moose this summer, so penetration definitely weighs on my mind. It was my dogs fault, so I didn't fault her in the least. I had a Ruger Redhawk on me, but I wasn't about to stand my ground with her, so we did some Chinese fire-drills around my truck. I learned that moose are fast and running in sandals sucks haha. I'll be backpacking in the Wind Rivers this summer, so I hope to have a reliable hardcast running by then. Thanks again!
New Post
1/3/2016 4:06 PM
I've using CorBon 200gr loads as a backpacking round when in griz country -

What drew me to them is they are supposed to be hardcast rounds with a FMJ jacket over them. Seems the best of both worlds for my G20. It is FMJ so it is good for Glocks. It is hardcast so the material under the FMJ should be a lot harder than the soft-ish lead in most FMJs. It has a listed velocity of of 1125 which is a little slow for a 10mm IMHO but it is what it is.

Carried the Glock 20 with this load on a four day backpacking trip in Wind River Range in 2014. Beautiful place and I hope to go back. That said, unlike Glacier and Grand Teton NP trips, we saw no large animals...found that kinda surprising.

Highly recommend Pinedale WY as a jumping off point. Great town with great folks there.
New Post
1/4/2016 2:21 PM

Awesome, I'll give those a look.

New Post
1/9/2016 9:00 AM
Just wanted to post an update since everybody here was so helpful. Took the stock Gen 4 Glock 20 to the range today. 100 rounds of FMJ, 20 rounds Hornady XTP, 40 rounds of Underwood 200 grain hardcasts. Overall, very happy. Accuracy/POI was spot on with all of these loads. I had two malfunctions, but I can't rule out limp-wresting and break in of the gun. I'm not two worried about 2 malfunctions out of 160 rounds in a brand new gun, glock or not. Those Underwood loads pack a punch, but were easy to control and keep on target. I have no doubt they're more than enough for anything I'll encounter in Colorado, except maybe my ex-mother-in-law. :) Thanks again for the help everyone, really enjoying this forum!
New Post
1/9/2016 11:15 AM
Have only shot this out of a carbine, and don't want to derail the thread, but if anyone here has advice on converting a gen4 g21 for 10mm I'd love to get a new thread going about that. Just posting here since I assume many g20 readers will be checking this. Plus if I can complete this conversion, then I'll certainly add my reliability experience here, fwiw.
New Post
1/10/2016 4:16 PM
Not the cheapest way, but I just bought basically a "complete upper" so that in order to make my G21 sf into a G 20 sf I take one slide assembly off, and put the other on.. Quick and easy.
New Post
1/11/2016 6:11 AM

An entire new slide and mags is the best way. G20 and G21 slides are different. There are ways to convert a G21 to 10mm (conversion barrel from Storm Lake if they still make one, change extractor/ejector), but I'm not sure you can go the other way without a full slide/barrel swap. The full slide/barrel method is the best way to ensure reliability. For what you end up spending, just getting another gun makes a lot of sense. Every time I consider setting up a conversion, that's the solution I come back to.

New Post
1/11/2016 6:27 AM
CCH wrote:

For what you end up spending, just getting another gun makes a lot of sense. Every time I consider setting up a conversion, that's the solution I come back to.


It's definitely the most fun solution!

HomeHomeDiscussionsDiscussionsFirearms and Sk...Firearms and Sk...Glock 20 10mm Gen 4Glock 20 10mm Gen 4