crimp dies
What is the difference between a "roll crimp" and a "tappered crimp" die. Thanks
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Like the names imply, a roll crimper turns the mouth inwards (rolled edge) while a taper crimper puts a slight angle / bevel on the mouth
Roll crimps are used on revolvers, and rifle rounds that are designed to be crimped (the bullet will have a crimp groove cut into it's side to accept the crimp), while taper crimps are used on self loading pistols where the case mouth is used to control headspace.
Roll crimps are easily visable to the eye, while taper crimps are harder to detect (the mouth will only be .004-.005 smaller than the case body)0 -
TG has it right. Roll crimp is used on brass that headspaces on the rim or the shoulder or on a belt - anything but the case mouth. If the brass headspaces on the case mouth (45 ACP, 9mm, etc), a taper crimp is preferred because it retains the case length, e.g. that front edge of the case mouth, for proper headspacing. Now, if you were shooting 45 ACP in a revolver and using a moon clip to retain the case, I guess you could roll crimp that. A roll crimp curls in the case mouth a little and probably holds the bullet better, especially if there is a crimp groove. Wish I could draw a diagram to illustrate. 0 -
If you go to the reloading forum there is a new STICKY on the top of the page from Yours truly on request of the MOD. It does nor dwell on the difference but tells at least one persons opinion on when to use each and how to adjust each 0 -
Roll (left) note top edge of case is turned in. Taper (right)0
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