Recently picked up a AR pistol with 8.5in barrel, took it out today for the first time to see how it shot. Well didn't do to good, it wouldn't cycle the bolt at all. So I got it home pulled off the handguard since I figured it was a gas problem.. Look like it blew a big hole beside the roll pin. Never seen that before. The gas block looks like some cheap jap made block with rails on each side but its still aluminium I never would have thought there is that much pressure to blow a hole in an aluminium block. Has this happened to anyone before? Any suggestions?