The first thing to consider is that you have a cast bullet "designed" for a gas check!
If so, there are gas-checks out there (I think Lyman) that are designed to just slip on! There is no crimping required for them, unlike the Hornady gas-checks that do require crimping!
I've used the Lyman brand and they worked fine! After you size the bullet, there will probably be a little lube on the base of the bullet and the lube will hold the gas-check in place while you seat the bullet!
