So the tale continues. It seems this is a Bushmaster ORC which has the Bushy logo on the lower but right next to it it sez Illion, NY so this settles the source question. After the initial debacle I took it apart, scrubbed it, and re assembled it with the addition of a Geissle (sp?) replacement trigger. Loaded more of the Sierra 165's this time with 40.2 grains of IMR-4895. Went back to the range at 100 yards and this is what it did; first pic is from the first session where it's not hard to figure out my distress, second pic done this morning. When I saw this you could've knocked me over with a fart I have no idea what happened here. I am happy, however, that it looks like I don't need to do all the things I was thinking of and now I almost don't want to clean it. Guess this barrel really hates 150 grain bullets.
The rifle does have a sharp, nasty recoil to it and it's trying to tear the rims off my brass on ejection. I'd put on an adjustable gas block but I'd like to retain the front sight so the fix is probably a heavier spring and buffer. Any suggestions as to weight specs?
Regards,
Mark