I run Southern Ammo .308 (boxer.berdan mixed izzy-belgium) in my 1919semi with few problems. The semi42 will blow these primers,but the ammo burns clean.
Romanian 8mm is corrosive, and cakes up quick, but it seems to fire nicely in the semi42. Clean barrel and bolt immediately.
I have been using lake city, the good stuff, I won't take a chance with crap ammo in my FAL. I have some .308 South African coming, berdan primed, non corrosive. gonna try that in the 42.
I use Turk in my 98. and for unloading into dummy belts. crap is cheap enough to burn. Haven't had any problems shooting it. No hang-fires, or mis-fires. Also shoot sellier-belloit sp in it to get rid of the feral cats at my in laws. Just bought a case of Yugo. have not had a chance to fire it.
Although I would not run turk in a 42 because it's hot and the brass is questionable. I ran a few thousand through my 1919 and it loves it. I wish I had bought more. You lose some to split necks like 5 per bando. I wish there was still a good source for it.
Have run about 10K of turk 8mm through my Mg 34 and 1919A4. Have tried ammo as early dated as 1938 and as late as 1950. The only turk I have had run well consistantly is the 1949 dated turk. No head failures, split necks etc and only an occasioanl misfire which usually would fire 2nd time through. I would avoid any turk dated before 1944 as the heads are much weaker than the later dated ammo. Of the 10K I've fired about 8k of it was 1949 dated. However I would not use this ammo in my 42. I only shoot Portuguese 308 or 8mm in it. In the 34 I have had good results with the early german brass case ammo J and G was selling a few years ago.
I run South African 308 in both my 1919's and my Fal's..every once and a while I get a misfire.. out of about the last 20 that I have had (out of 3000 + rounds) only one did not go off the second time thru. I also have purchased the linked 308 from England M13 links-160 rds to a can-$ 20.00..This stuff is GREAT..I run it in a friends M60 and in my Fals..I have also tried the Port. 308..it worked fine also..I have not shot alot of it but from what I saw it was almost on par with the South African. I will not shoot the Indian ammo in anything I own. I have witnessed one gun get destroyed and have looked at another that had the brl. damaged beyond repair. The latter was a 1919 so the fix was cheap and easy..The first was an original L1A1...Demo'd it..So a word to the wise...Don't try to save a buck ...buy quality ammo and play it safe..
This is why its good to get a 7.62 NATO (.308) conversion kit. 8mm is a great round but is getting somewhat limited. If you invest in a good MG3 .308 barrel (possibly a smaller or .308 nozzle if needed), NOS MG1 top covers and feed trays can be had for $89...and that opens up a world of alternatives, including some very recent made good surplus NATO .308. Just my 2 cents...