Hmmmm, I must be the outlier. I reload and I run an 8.5” barrel with and Octane .45 suppressor (not really any gas blowback since the can is oversized).
Just finished testing a lot of different loadings, found some very soft 115 loads that I tailored to run at around 1000 FPS in the Uzi so they stay subsonic, tested in semi to get chrono readings and no issues with it missing the sear. Runs good enough for plinking and very quiet so it doesn’t bother the neighbors. ROF is somewhat inconsistent but no worse than say CCI Blazer Brass 115 gr, which my gun runs just fine but it is supersonic.
I have some Winchester 124 NATO on hand and that stuff is powerful and consistent, so I can see why that absolutely would be the go to for military usage, but it is too loud for me to shoot at home a lot.
My next reloading Runs will be heavier 129 gr cast and 147 plated so I won’t have to load so light to stay sub-sonic.
I tested the same loads in my semi SBR and the worked fine in it as well. In the past I has some very old weak reloads I made for my wife, they would not run the semi auto but ran the FA UZI surprisingly ok.
I tested my best two recipes in the FA Uzi, SA Uzi, 4” AR, Glock 43X, and Glock 17. One recipe ran everything but the G17 well, so I scrapped that one and went with the other. Velocities were so low in some of them you wonder how they cycle- but they worked fine. Quality guns can always take a wide variety of ammo.
Funny thing with my Uzi- it was brand new when I got it, I needed to fix some issues before it would even function at all. It was a bit more troublesome early in, but as it apparently wore in I have had the reliability just get better. Usually I have zero trouble now with it. Ran into something the other day and was astonished to see it having malfunctions as it had been so long since it has any at all. Apparently it had also been a very long time since I had checked on the top cover as it had disassembled itself and was as a result stopping the bolt. Swapped top cover- good to go again. Took the bad top cover apart to fix it (not for the first time) and parts went flying and are probably lost now...oops. Good thing they are cheap. Adjusted two covers to the Uzi last night so the bolt gap is ideal again.
Only ammo I tried so far in my Uzi that did not work well was some old Blazer Aluminum cased stuff as I wanted to shoot it up, had one casing kaboom itself and realized it is not meant for open bolt guns. Had lots of malfunctions with it as well. Amazingly their brass cased version you can get today works better.