First post. Just got a Glock 20 Gen 4 (w/nickel boron coating) and have been lurking here for a while. I have a few questions and if these topics are covered elsewhere please point me in the right direction. My new gun procedure is to clean, inspect and lube, and then fire 100 FMJ to see how it operates. If all is good then I try a magazine of this ammo and a magazine of that ammo, looking for any issues. If no issues then I clean, inspect and lube and I'm good to go. If issues w/one specific ammo I avoid that ammo.
Now I'm reading about 10mm ammo in some cases being "hot" and resulting in "case bulging" from being "unsupported". I have to admit I haven't dealt with these issues before and could use some information.
I bought some Remington UMC 180 FMJ for break-in, and ordered some DT, BB, and Underwood ammo in various loads for testing. The gun is 100% stock and with the exception of a "$25 trigger job" I don't plan to modify anything and will use OEM parts if ever needed. Stock 5+ lb trigger pull will be fine.
What about the recoil spring? I've always bought OEM or Wolff springs but never experimented with anything but stock rating. Given those "hot" rounds should I consider a stronger recoil spring? If the gun operates 100% with all ammo is there any reason to increase the recoil spring force? Realistically I'll probably shoot 300-500 rounds a year.
Thank you for your time.
You will get a range of opinions, I'm sure.
I have a Gen4 G20 and I ran different barrels, different springs, in different combinations. I'm back to the stock configuration and I have no intention of changing from that again. It runs. It doesn't mess up. It eats just about anything you throw at it. The extra money I've thrown at it early on was simply wasted.
I will say one thing though. The factory chambers are designed to be loose to encourage feeding and will allow for more expansion of the case with heavy loads. If you don't reload it won't be an issue. If you do, just keep in mind that the more the brass is worked in sizing/firing the faster it looses it elasticity and become subject to fail.
Smiles are a different condition. If a load smiles, I don't go with that load again. Its a pressure sign in its extreme. DON'T reload a smiled case either. I have had two factory loads do this, but only did it with my Glock. The Witness pistols fired it without any problem.
Greg
No issues with my G20 and Underwood, Doubletap, and Buffalo Bore ammo and the brass they use.
For the hot stuff (Underwood) you might want to consider a 24 pound RSA. This seems to vary though, from gun to gun and shooter to shooter.
This is a Glock, not your Grandfather's new Colt. I do not recommend a "break-in cleaning". A disassembly and inspection is well-advised, of course. Just put it back together and shoot it until it "needs" cleaning. If all you shoot is factory ammo, that will take a while. At 300-500 rounds/yr, an annual cleaning is more than sufficient, unless you get some really dirty stuff. These things just don't have all the problematic, intricate, micro-parts of days gone by, and modern name-brand ammo is cleaner than ever (especially with a longer bore).
You have had some good advice.
Fact is Glock employed some pretty good engineers to design the G20 for 10mm. It kinda stands alone as a gun designed for 10 and then later released in a 45 ACP version, rather than the other way around.
Smiles mean ammo is over spec most likely. You might see some with Underwood and Buffalo Bore. They both claim they are within saami spec, but I personally do have my doubts they haven't creatively interpreted some of the data.
As a general rule, there is no good reason to change your Glock from stock unless you have a specific problem to fix or goal in mind. For instance, I have a Zev 3.5 rocket connector for mine for accuracy testing. Specific tool for a specific purpose. And that is the great benefit of the Glock. I can change the connector in about 90 seconds.
Good luck and let us know about your experiences in range reports!
OK, I'll submit a range report in the appropriate section once I've done some shooting. Thank you all for the comments and information. I also have a Glock 21SF (and some XDm's) so I'm familiar with the platform but I've never changed to a different recoil spring on any gun (never had an issue). I used to do a lot of reloading (revolvers) and all I ever found were flattened primers and a reluctance for the brass to slide back out of the cylinder indicating a need to back off on the charge a bit. The pictures of Glock "smiles" is something I'd find alarming if I hadn't heard of it here. Actually it's still gonna be alarming if I happens although the loose chamber explains it. In the revolver world I'd resize and reload the same brass a couple dozen times with no problem.
Thanks!
A bulge can be reloaded. The smile, not really suggested unless you really like to experience case head seps.
I have a shooting buddy who reloads 30 carbine for a Ruger Blackhack. And he loads nuclear. Your comment about cases being reluctant to eject made me think of him. I shot that gun once with his reloads and decided there wasn't enough safety gear in the world to convince me to take another shot!