I had a little trouble with the new 18" barrel combo this morning. After tuning the gas setting, it was running really great. On round 75, I had a OBD and blew the bottom of the carrier and an aluminum mag apart. The cartridge head was left on the bolt face and separated from the case body. 90% of the case is still in the barrel. The bolt still rotates in the carrier but the extractor is bent outward. Even thought the bolt lugs were unlocked, the bent extractor made it difficult to separate the bolt from the barrel collar. I had to take the upper apart to get the carrier and bolt out.
I'm taking the new 18" Ballistics Advantage barrel to a gunsmith to look at the chamber. It looks ruff. I want to inspect the neck area of the chamber with a probe. It was really a challenge to remove the case. I had to cast the throat and push the case out.
I think the Cry Havoc QDB is part of the problem. I would not recommend using the system with the Max system until we know more about the problem. I think there may be tolerance stacking issues.
I will send the A1 upper back to The Wizard this week for inspection. The charging handle rod is not sliding easily. The receiver may be bent. I really hope its repairable. I love this thing.