I got an empty case stuck in the barrel today. The case wasn't deformed but, it did have some carbon around the casing. What causes this? Dirty barrel? Wolf ammo?
I clean the barrel after I shoot, usually 250 rounds a time, with cleaner and patches. However, I only cleaned the barrel with the brush once. I have about 1000 rounds through the gun with no problems till this. Thought I would ask the experts, still new to the AR world. Thanks.

