So I stepped into reloading 12 ga brass hulls for Cowboy Action Shooting. I got a really good deal on 100 Magtech brass hulls and the RCBS Cowboy dies. Unfortunately the dies are 1¼" and wouldn't fit in my Hornady or Lee press. Apparently they only fit about 5 presses out there. So I ordered an RCBS Rockchucker. Can't really complain because we all could use another press.
I loaded some test rounds up and gave them a nice roll crimp. After firing them off I noticed that the roll crimp didn't quite completely straighten out. I tried to test putting a fiber wad in and it was tearing it up. The bad thing about the RCBS dies is that they don't come with a case mouth expander.
I thought of different things to try around the house and nothing really worked exactly how I wanted. They came close but not right. Well I'll just have to machine something at work tomorrow I thought.
I walked by some parts that I had and noticed an H1 buffer that I replaced in one of my AR's. I broke out the calipers and took a few measurements and it was right on the money. It even had a nice slope on the shoulder before the full expansion. I dropped it right into the die and fit exactly where the roll crimp piece is installed. I did have to take .025 off of the length of the buffer with a file.
So if you need to get the roll crimp out of your brass hulls, now you know what to use.