I've done that a couple of times with no problems. You could check it out by firing just a cap/primer to see if all is good. If that works then leave the spent primer in the BP to act as a buffer/snap cap when you want to check the trigger pull. This is not ideal but should work better than just dry firing. Another idea is to put a peice of rubber, like a faucet washer without a hole, between the bolt face and the BP to cushion the fireing pin.