RR, it's not very dramatic story. I had made it a practice to trim my revolver brass to minimum to aid in uniform roll crimps. On my first venture into auto loading I did the same thing, but for some forgotten reason I took a bit more off from a group of WW 10mm. Fired cases showed very flat primers with moderate loads which I could only assume was due to high pressure which made no sense to me, but I ditched that batch as a precaution. Looking back thirty years I am sure the flat primers were from too much headspace and pressures were normal.
The only thing I can remember breaking on that Delta is an extractor, not sure if the short cases contributed to it or not. I have read the threads where guys claim to have fire .40 S&W in their 10mm Glocks, it amazes me.
Now I never even check the length of auto cases, taper crimps make it pretty pointless and, as Swifty said, it takes a lot of firing and reloading for them to grow, I've usually lost the before it can happen.
