I’ve got a roll crimper and am interested in roll crimping some 12 ga ammo. I’m using a hull which has a 8 pt star crimp, a WWAA compression formed hull. Can I simply roll crimp this hull or do I need to ‘skivvy’ out the star crimp so it rolls properly? I’ve tried it with the star crimp, doesn’t work too good. All my hulls have this star crimp, I don’t have any smooth, unfired hulls.

Not in my experience. I buy longer hulls and cut the crimp off before rolling.

Seems pretty unlikely, even without trying it. I cut back a lot of hulls for my vintage German drillings and combination guns and they roll crimp nicely. I can only assume you need to get rid of the star crimp or do as 5 shot described.

Cut off at the bottom of the star. Put a over the shot wad on top of the shot then roll your crimp. To get more explanation. Go down to 16 ga society. Them guys roll crimp as much as regular crimp. They'll give you an detail explanation.

Federal and cheddite hulls are REIFENHAUSER straight wall hulls. Never heard anyone having any luck roll crimping AA STYLE HULLS or with the kind of plastic used in them. BP makes crimp doctor tool you chuck up in a power drill it skives the hull mouth gets it hot and takes out most of the fold memory. If used to long it will stretch the mouth diameter out. You be way ahead to plan on using cheddite hulls. MB

I've done it by trimming off enough of the star crimp (about 2/3) to get the hull the correct length for a 2 3/4 load column. Roll crimps require less hull length, so this works. When most of it is trimmed off the issue is largely resolved. Any hulls that still look "crimpy" after this get a short pass at the skiver. Won't take long to get the hang of this.

Same here, cut down to 65mm for my old Euro sxs and pretty much use 2 3/4" low pressure loads.

Cut down Rio Target hulls.