Quoted:
If you follow any of the FAL groups on Facebook or listen to Mark Graham of Arizona Response Systems, then you will quickly find out that the issue is not with just steel cased ammo. More specifically, the issue is with TULAMMO .308. I personally had TULAMMO KB on the second round in my FAL. Blew the bottom out of my magazine. Rifle was a new build that headspaced perfectly before and after the KB.

I have fired near 1000 rounds of steel cased Wolf and over 1000 rounds of various brass cased ammo through my rifle with no issues. Second round of TULAMMO  was a KB.

Bottom line is, most steel or brass cased ammo is fine. TULAMMO is NOT OK.