wabi

One of my A&H's use to do the same thing start out really nice then have a spot of difficuty. It was as learned later blow back running back along the threads of the BP to a point and stopping. At that point the crud would build up. It stopped doing that when i switched to teflon tape, overwrapped the nose of the BP and installed it snugly to stop the blow back at the face of the breech plug.

Be sure to look into FG advise make sure the BP barrel threads are clean - I use a bronze brush chucked in a drill and a little bit of Orange Citrus Cleaner Degreaser to clean and polish threads.

Hope you get it figured out..

The 300's sure shot nicely - actually all of them would have done an animal in...