Problems with Wolf Ammo

[Captk]

Took the rifle out today with the Tubbs weight installed. I had to remove a small amount of material off the bolt carrier for it to fit. I started with wolf ammo, 1 round, 2 rounds, 3 rounds, 4 rounds, adding 1 round to the mag. I did have 1 problem with the round chambering but a slight pull on the charging handle and the rounds chambers. No issues with extraction until I had put 30 rounds through. Then I was right back to where I was last week with every round getting stuck in the chamber, this was with both the wolf and hornady ammo. I no longer feel this is an ammo issue. The first 30 or so rounds all fired and extracted fine. Any suggestions? It seems the chamber is getting quite dirty and causing the problem. I don't want an upper that can only go 20 - 30 rnds then malfunctions.
Ken