Dif Between Roll,Taper and Factory Crimp

[88 man]

Hi Guys
I'm starting to reload and wondering what the diff is between roll,factory and taper crimps are.I will be reloading for my Winchester 86 in 45-90 and want the best crimp with least extra pressure.I have a 2 die set and the seating die will roll crimp.Any info would be great or what what do I have to buy.
Thanks, 88

 

[tiriaq]

Roll crimp - your die has a liitle shoulder that causes the mouth of the case to be turned in toward the bullet, into a crimping groove. Uniform case length is critical for uniformity.
Factory - Lee crimping dies can do this. Collet fingers are forced into the case - and into the bullet - laterally.
Taper - the die is tapered over a relatively long portion, and the case is given an even taper against the bullet. Usually used on rimless auto pistol cartridges. Can also improve feeding.
Your factory die will do just fine for your .45-90 '86. Classic rifle.

 

[sunray]

For your .45-90 a light roll crimp will do for light loads. A slightly heavier roll crimp for hotter loads. The purpose is to stop the bullets moving under recoil in the mag. You adjust the seating die up or down a tick to add or lessen the amount of crimp it puts on the case. How much is a matter of trial and error. Excessive crimp can affect accuracy. Use just enough to keep the bullets in place.
The taper crimp is for cases that headspace on the case mouth. Like tiriaq says, usually semi-auto pistol rounds. Your cartridge headspace's on the rim so a taper crimp die wouldn't be needed.