Casting for the .500 with 2 different molds. One is a Lee 440 grain and the other a 700 grain made by a well known machinist/BP shooter. I tried to find hornady gas checks,but looks like they aren't made any more. So I ended up with gator checks instead. On both molds some fit and crimp tight,some are loose even after trying them a couple of times. I tried to anneal them with no good result. It seems like if I place the GC by itself in the sizer,run it down,snap it on a slug,then it grabs.But even this isn't a 100% solution. The bases are filled out good,sizer die is .500....any thought as to what a person can do? I was also thinking of trying a round coarse file,twist it around the inside of the GC just on the wall to rough it up then seat it...I never had this happen with any rifle cast slugs. The velocity is also under 1500 FPS for them,,so maybe just go with out them?