I bought a Glock 48 with black slide recently, brand-new, made in 2020. Love the grip and accuracy. But the gun just chokes on weaker 115-gr ammo. Multiple failures to return to battery, stovepipes, FTEs. The factory RSA falls off when the gun is field-stripped. Bought another factory recoil spring assembly, the same story. Yes, ammo labeled Target Sports USA, no go. WWB 115, no-go. Can't get through a mag with it. Federal 124+P fired fine, but with the ammo this expensive these days, this is a bummer. Is G48 generally ammo-sensitive? What is your experience with G48? TIA

Mine has been fine but I did put maybe 200 rounds of 124 NATO though it first...which of course is tough these days. I have not noticed any issues with weak stuff.

I had a couple malfunctions with 115gr practice ammo when the gun was new. Recently replaced some magazine springs with "extra power" springs, and again experienced one malfunction on the very first mag (also 115gr practice ammo). The problem then went away.

It does like the hot stuff, and with weakish ammo will reward a firm grip. My RSA also falls out very easily.

Glocks usually don’t need a break in to run powderpuff stuff but I would run a box or three of hotter and or heavier ammo through it, make sure it is well lubed and maybe leave the slide locked back for a few days then re-assess. You might want to work the slide with some dryfire as well.

Also, and I mean no disrespect with the question, but could you be limp writing it? Fairly small gun, fairly fast slide velocity usually needs a pretty strong grip.

Try the break in routine above and then re-assess and send to Glock if necessary.

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Also, and I mean no disrespect with the question, but could you be limp writing it? Fairly small gun, fairly fast slide velocity usually needs a pretty strong grip.

No, I am not limpwristing. Been shooting various Glocks since about 1985, both issued and bought, LOL. Qualified as master in PPC many moons ago. My G26 shoots the same ammo fine. I think G48 RSA is a culprit. The spring is designed for the hot ammo. Yes, and for 200 rds of good NATO ammo they're asking $120-130 around here, if you can find it. I have plenty of reloads, but G48 is no good for this stuff.

As far as the spring is aware, all +p or NATO-spec does is deliver a full compression with each shot.

So, you can achieve the same exercise of the spring with manual cycling. You re-set this process in your gun by replacing the RSA.

Of course, shooting may do a few other "break in" things that are beneficial to the gun, due to the high speed of the cycle (parts smoothing and mating correctly, etc). But the spring doesn't know the difference.

Here are a couple other things you might want to do/check:

1) Ensure the extractor and its channel are particularly clean and dry.

2) Consider carefully polishing the connector. It's possible that you have a few rough surfaces that are robbing just enough recoil energy to make a difference with light loads.

Hmmm... Mine has been trouble free. About 1K through it. Main practice load has been Fiocchi 115 or 124, depending on what was cheaper.

Send it to Glock to fix.

Is the pistol lubricated?

My G48 runs fine on everything put through it, including some powderpuff 9mm reloads.

I have well over 2000 rounds through two 48's, mostly S&B and Fiochi, both 115, but might be a little bit hotter. Zero issues.
Sorry for your trouble. It's a great gun.

Lightly polished the trigger bar, installed Apex connector laying around, got one box of Speer Lawman 115 gr from a friend and shot it today through G48 with no issues. Then shot light reloads and got failures to return to battery. I think I will be getting there, the question is how much I can invest in a good hot ammo. But I expected better from G48.

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Originally posted by hessy2000:
Lightly polished the trigger bar, installed Apex connector laying around, got one box of Speer Lawman 115 gr from a friend and shot it today through G48 with no issues. Then shot light reloads and got failures to return to battery. I think I will be getting there, the question is how much I can invest in a good hot ammo. But I expected better from G48.

Instead of dicking with it and wasting ammo (and money), contact Glock, send it back, and let them figure it out..
As you can see, many a member had no such issues with their G48..
Give Glock a chance to fix it before you get too butthurt about it...

Of curiosity, I pulled my a G48, G43X, and G43 out of the safe; same recoil assembly, same fit. None fell out; all were retained under their own spring tension. The slides are interchangeable. All three pistols function with my own reloads, whether full house or reduced power. Same factory recoil spring assy.

Never a fan of the Glock single drop of oil theory, I grease mine and lubricate them with oil, too.

Mine has been perfect and I love it as a carry, as mentioned above I would just call Glock and let them fix it if there's a problem. That's what warranties are for.

No problems with mine. But haven't a whole lot of ammo through it yet.

2020 austrian made gun.

My G43 functions well on light loads that my G17 will not.

The G48 I shot on range demo day did fine with typical rental range econoball.

I think yours is defective and trying to "break it in" with expensive ammo is a waste. Complain to Gaston.

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I think yours is defective and trying to "break it in" with expensive ammo is a waste. Complain to Gaston.

Since I retired from the force, my experience with Glock's warranty service has been iffy. You pay lots for overnight shipping, and the returned gun did not have its problem solved. I have lots of parts laying around-just not for G43/48. I am thinking my old G26 and Gen 5 G19 are enough. They are 100%. G48 will be gone, sadly.

Well geez. I'm about to retrieve my G43X out of background check purgatory and this is the sort of stuff I get to look forward to?

None of my customers that I've sold G48s to have come back reporting cycling problems with their guns. I know some of them have been using whatever ammo they could source, like the "white box" ammo from Winchester and Federal. Or any of the wimpy Independence brand that we had for a while; I do remember selling someone a G48 and a couple of boxes of that latter stuff. Never heard a complaint but in truth I also don't know if she's actually taken the gun to the range since that purchase.

At the very least I'd try to run a box or two of 9mm NATO through the gun before again trying any of the known weak loads like WWB or bare minimum SAAMI spec 115gr Blazer Brass. Glock would probably tell you a similar thing. An old coworker had a Gen4 G19 that initially choked quite a bit, but after shooting a batch of 124gr and 147gr range loads (maybe 150 rounds at most) his gun loosened up and was 100% reliable afterwards. Normally a G19 is not a model that anyone would think of as requiring a break-in period, but in this age of stacked tolerances even with normally loosie-goosie built Glocks it sometimes happens.

The problem with sending it in for warranty work is that they'll probably test fire it with a few mags of Sellier & Bellot (or whatever), experience zero malfunctions, and send it right back with a terse note.

How do you explain to the factory that they really need to test it with the lightest, marginal-power reloads?

The gun now works with Lawman 115gr FMJ, but still chokes on light reloads -- that's a substantial improvement. I'd manually give the slide about 500 full cycles and try once more with the light load of choice before dumping it.