Joe in Missouri ,”I am grateful that pistol primers did not drive the bullet far enough to chamber another round.” Don’t depend on that statement, I had an undetected squib in a P229. The result was pretty loud and I Sig said it cracked the frame. I will never know for certain but the best opinions I have received was no powder as the cause. The round in question was loaded on a 550 using poly coated .40 bullets. Best guess is I left the 550 for some reason and lost track of the process. From that day forward when I leave the machine I either empty it prior to leaving or before I re start the process.
I hope this helps keep someone else from making the same mistake I made.
