Over-gassing/Timing Issues

[popgun]

I'm by no means an expert ... but, could it be you have too much headspace? My fired brass measures 1.190-1.191 and resize to 1.188 or a half thou under that. Your around .008-.009" of headspace if your chamber is close to what I've seen common for dimensions. That would be working the brass pretty hard and don't think it would last as long as most before signs of case separation. My novice opinion should be taken with a chunk of rock salt.