New to me Thompson Blackdiamond (22 /12 barrel).
First range session second shot the primer retention spring breaks! Now I need help to determine if it was user error, defective/old, or just bad luck.

Particulars.
The rifle was a pawn shop purchase. It looked like new, may have not even been shot. Yes I know this model is a few years and that may have contributed to the failure.

90gr tripple7 FFFG
Hornady .430 300gr hp/xtp
green crush rib sabot
Winchester W209 primers
Pink tape on plug.
swabbed between shots with windex/alcohol mix. Then 3 dry patches. (could some alcohol have gotten into the breach plug?)
Approximately 5 minutes between shots.


Any Ideas on what happened or how to stop this from happening again?


Thanks, Mitch







Also what the hell is this piece? It came out with the primer and does not seem to be broken off or missing from anywhere.