Wow,
I know how unnerving that is, I blew up a Sig P220 in 95" using some over pressure +P+ .45 rounds loaded in cut down .45 Win Magum cases. When it occured I was not sure what had happened from the smoke, but as it turned out the magazine blew out all of the remaining rounds and the follower/base plate, the mag body was completly wedged into the frame and could not be sperated. The Hogue rubber grips actually expanded about an inch in diameter on the right side and I could not sperate the slide and frame, the slide was still on the frame by about 1/2".
The front of the slide actually tore through the alloy frame and came to rest where the mag usually came through the grips. I never found the back of the casing and my shooting glasses where dimpled from powder flakes/metal or something. I returned it to my gun dealer as an FYI and the Sig rep actually came out and picked up the P220, they gave me a voucher towards a new one and requested I transfer the gun to them. I picked out a new P220 and secured it in one of my gun closets, I later found it in 99" and Garrity laughed at me for forgetting I had a Sig P220.