I botched installation of a "White Lightnin" vent liner in my .50 cal. T/C barrel. I must not have cut the threads deep enough and in seating the liner "manned" it in and must have just about wrung it off. I could see a surface failure in an arc about 1/3 of the way around the opening of the vent indicating separation within the vent liner.
I figured if it blew out it was just going to hit the side of the smokehouse, but after several shooting sessions, it was apparent that I had sacrificed both ignition reliability and accuracy from it's previous self...and I just didn't trust it. It's not a great barrel but it has been a decent barrel. I just can't leave well enough alone and have been installing "White Lightnin" vent liners and peep sights on about all of my rifles. I was now shooting 12" shotgun patterns all over the target at 50 yds.
Back to the gun room, I removed the liner, cut the threads a little deeper and installed a second "White Lightnin" liner, being a little more careful this time.
Back to the range, accuracy has returned. In fact, of ten shots fired at 50 yds into a 2" orange bull, all have been contained within the 2" bull.
Everything else had remained constant as far as variables go. Same lube, same ticking, same balls, etc. It was the poorly installed vent liner.