22-250AI shooting 80gr Berger VLD 8" twist 26" BBL. H4831 43grs produced avg MV of 3,340 with a couple of cases with shinny ejector marks.... 39grs of IMR 4007 produced avg of 3,365 with no pressure signs. Both produced about same accuracy 1/2 MOA at 100. What is happening in chamber? I thought the slow burners were the ticket when firing heavy bullets....