well i finaly started a project old 22 lr well worn . made a few screws purchased a barrel from green mountain chambers it cut a extraction slot in it. went to the range in 6 shots the head space opened up about 40 thousand failed to fire any more. started to wander why and it old and worn i welded the back of the breech block filed and polished it down till it was snug. went back to the range put 100 plus rounds through it worked like should have a lot of work left