I recently acquired a new-to-me G48 with the black slide. The one opportunity I had to shoot it, I had 2 instances (out of 200 rounds) of it failing to go fully into battery. I was shooting factory ball ammo.
Attempting to diagnose the problem at home, I've discovered that when the trigger is held back and the slide cycled, even if it is allowed to cycle freely, the slide stops just
short of returning fully to battery until the trigger is released.
Disclaimer: I am not as familiar with the newer Glock trigger systems as I am with the Gen 2 and 3 system. I did own a 43 briefly (<2K rounds) and don't recall this happening. It definitely didn't have return-to-battery issues, though.
If I release pressure on the trigger slightly, It will go all the way forward. With the trigger held back after racking the slide, I can press the trigger back and forth (without letting it far enough forward to reset) and watch the barrel hood move up and down relative to the slide as well as the slide moving back and forth. This is on the order of a few hundreds of an inch of movement... similar to significant endshake on a S&W.
If I press on the back of the slide, I can still feel this movement happening, albeit to a lesser degree, so I don't believe it is simply a weak RSA. What it feels
like is the striker spring running out of compression, but I have no idea how to determine that for sure. I did disassemble the striker assembly and check for burrs on the back edge. There was a slight catch, but even after I smoothed that out, there was no change in what is happening. I compared the striker spring to an old Gen2 striker assembly and discovered the spring from the G48 was actually about 1/4" longer than the Gen2 one. I swapped those springs out... still no change. Trigger pull weight and reset seem unaffected as well. Both are stock springs so that makes sense.
I also checked the striker safety spring and it is functioning properly.
I tried it with a dummy round, and while this eliminates the up-and-down movement of the barrel hood, the slide still goes back and forth.
The pistol is bone stock. I did a very mild fluff and buff with 1000 grit wet/dry paper in appropriate spots.
1. Striker spring overcompressing
2. Trigger bar too long
3. Too much overtravel
5. It's normal
Anybody have a clue? Here's a video.