I have read quite a bit about the dangers of using Tula ammo in any rifle chambered for 7.62 NATO, but have also been told that Tula and Brown Bear will work well in a CETME, G3, HK 91, PTR 91 etc. Of course there is always someone who claims that TUla is dangerous in an HK91 and that case head separations are common, but could any issues such as the round failing to fit properly and the mag blowing out of the gun, damaged receivers etc be caused by shooting it while filthy? Also, has anyone had issues shooting Tula from a clean! HK91? Not trying to rehash what has been discussed on other forums, but I wonder if cleanness has something (everything) to do with it.