I have one with the screw in breach plug. The push out ones were only a problem after a hang fire, people would open the breach and if it was just a delayed fireing the breach plug became the bullet which went through a couple of peoples heads. They shoot great, just remember if you have a misfire wait a very long time before opening the breach, and stand clear of it. The fireing pin is very fat and flat ont the end, it will not work with a rifle primer. They are like a 1 in 60 twist, will most likely only work with round balls. Larry