nuge
More info is still needed.
What caliber is it? Only 40 rds, does this mean it is a new gun, new barrel add-on or new to you?
SB-1 receiver, or SB-2?
Is this factory ammo or any military stuff or hanloads (back to the caliber question).
We'll gladly help but need more from you. As was mentioned, it sounds like hot loads. by the way, if these are too hot IT COULD EASILY BECOME A BIG DEAL.