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**44 AMP** · January 19, 2015, 12:08 AM

There are only two possibilities. The gun is at fault. The ammo is at fault.

From the picture, the rounds are grossly bulged, from either a "generously" relieved chamber (feed ramp area) OR the chamber is normal and the rounds were overpressure, causing the bulge.

What you describe is the classic case rupture, caused by either too much pressure, or not enough case head support for the pressure involved. If you could find the case, I'd bet it ruptured.

Gas dumped from a ruptured case in an auto pistol vents mostly down through the mag well, sometimes popping out the mag. One pistol I saw it happen to kept the mag body in place, and the floorplate blew off, dumping the spring, follower and remaining rounds on the ground.

Also, as you found out, there can be a small amount of "shrapnel" (fragments of case) that can come back at you from the ejection port, as well.

January 19, 2015, 12:08 AM	#3
44 AMP Staff Join Date: March 11, 2006 Location: Upper US Posts: 30,484	There are only two possibilities. The gun is at fault. The ammo is at fault. From the picture, the rounds are grossly bulged, from either a "generously" relieved chamber (feed ramp area) OR the chamber is normal and the rounds were overpressure, causing the bulge. What you describe is the classic case rupture, caused by either too much pressure, or not enough case head support for the pressure involved. If you could find the case, I'd bet it ruptured. Gas dumped from a ruptured case in an auto pistol vents mostly down through the mag well, sometimes popping out the mag. One pistol I saw it happen to kept the mag body in place, and the floorplate blew off, dumping the spring, follower and remaining rounds on the ground. Also, as you found out, there can be a small amount of "shrapnel" (fragments of case) that can come back at you from the ejection port, as well. __________________ All else being equal (and it almost never is) bigger bullets tend to work better.