Since "I did buy a Glock!" I've seen lots of range reports, reviews and lots of satisfied shooters. What I haven't seen is them being picky about ammo, they need a break in before they stop malfunctioning, or that they'll get beat up with full power loads unless you put in a stronger recoil spring.

Is there just some kind of built in magic that they will run varying bullet weights and powers of ammo without hiccup? I've never seen any complaint of not cycling or suggestion to run a different spring for whatever ammo except maybe to run hot outdoorsman ammo in 10MM.

Interest in this as well. I haven't seen any reports for 9mm but have seen suggestions to use a different spring for hardcast 220gr bear loads vs the 180gr regular loads but only in a long term context (which I've basically been disregarding and just keeping the stock springs). I will hopefully never have to fire the hardcast 220gr rounds.

Note: the only issue I've had is with the brass to face issue with 9mm 115gr. Never with 124gr. But they've always cycled well (other than the issue with 10round mags needing the proper follower for use with HP bullets).

The G17/19 use the same recoil springs as the G22/23. I always thought that was a bit of Glock engineering magic that the .40S&W versions didn't require heavier recoil springs.

If you get into aftermarket barrels & slides, they are more likely to be picky about ammo &/or require break-in. If you run a compensator, you are more likely to need to experiment w/ different weight recoil springs.

10mm is loaded to a broad range of grain weights & chamber pressures, so if you shoot a broad variety of ammo loadings, it's recommended you tune your recoil spring to your loading. This applies to all 10mm handguns, Glock or otherwise.

I’m not a 10mm owner, but between my Glocks in 9mm and .45, Original has worked great in a bunch of different bullet weight, p, +p, +p+…

Somewhere down the line I switched from the plastic guide rod to a stainless steel one. I stuck with the standard weight springs.
17lb for my G-17, G-34, G-21.
18lb for my G-19


***thinking about toying around with the idea of going to a 19 lb spring on my G-34, solely because I’m mostly pushing +P or +P+ out of it.

The Glock is the pistol equal of the ak-47 of the rifle world for good reason. Both don't have tolerances like on an ar-15 or other semi-auto pistols. They aren't over complicated and that is why they run so well. They will both need minimal parts replaced compared to other guns and just function as they should. I have had many of them over the years and can't remember at anytime having an issue with one of them not functioning/working as it should.

The design is a great one,especially one that can operate a 9mm and 40 S&W pistol of the same size and I think that is why they really haven't changed with their design until now, due to the switches. Of all of the guns in the market today, if I had to trust a gun right out of the box without firing a shot through it, it would be a Glock.

Glocks will normally just run. We abused one gen3 Glock 31 without changing the RSA. It got over 7k rounds before a locking block pin broke in half.

This is one of those don’t overthink it scenarios.
Take the gun out of the box inspect and lube.
If it runs on your ammo, ( which it invariably will) leave it alone.

More recently some people have been reporting that initially new glocks won’t run on cheap light load 115’s and to shoot 124/125 or 147 for the first few hundred.
My gen 5 19 ran everything out of the gate, but my 26 wanted my practice reloads to reloaded hotter to run for the first 500, after that it ran fine on my typical middle of the charge chart load that it first refused to run

Usually the only time Glocks start having issues is when you start messing with spring rates or changing OEM parts.

I think the whole spring thing is a little bit clouded by overthinking on a locked breech gun.

Most of the energy of the slide is held up by it being locked. Until the pressure drops to a safe level. The recoil spring slows its rearward travel down at the end of the cycle and the energy stored is then needed to strip and chamber the next round. The weight of the slide is doing a lot the work also, both ways.

I recall people breaking slide stops on 1911’s when they felt they needed a heavier recoil spring.