Taper Crimp Vs. Roll Crimp

[rod locker]

I have seen and been told to use a taper crimp form my ammo.  Shooting 158 grain bullets wth 3.5 grains of 231 Powder.  Other sources say to use a roll crimp including the customer service rep at RCBS.  The rounds will be use in a revolver and also EMF 1873 rifle for CAS.  Should I stick with the taper crimp?

[Delmonico]

I don't know anyone who has used them who has went back to a roll crimp.

[Marshal Deadwood]

For what it's worth. I sometimes use a Lee factory crimp,,but more now I use a taper crimp myself. I think its more consistent than a roll crimp by a good margin. I started using taper crimp on buffalo rifles rounds,,, now I like a taper crimp on my handgun rounds.

just sayin'...

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[Shotgun Franklin]

I've used the taper crimp for years with very good results. I've even used bullets without a crimping grove in my .45 Colts with no problems.

[bowiemaker]

What is the advantage or benefit of a taper crimp over a roll crimp?

[Delmonico]

With a roll crimp you can't crimp a bullet with out a bullet groove, you can with a taper crimp.  Also with a roll crimp if you try to crimp a round too tight it will pull the case below away from the bullet.  This can happen with a case that is a bit longer than the one the crimp was set up for.  This can reduce bullet pull and in some cases it can prevent it from chambering. 

[Shotgun Franklin]

The other advantage is that you don't have to trim cases. The taper crimp die basically squeezes the case over a portion of the bullet rather than just in one spot. It doesn't matter the length of the case. With a roll crimp since you’re working on the mouth of the case then lengths need to be fairly close together.

[bowiemaker]

The paper that came with my Lee Carbide Factory Crimp Die (.45 Colt) says that it does a roll crimp and it will form a crimp groove in the bullet.

[litl rooster]

From the Lee Crimp die FAQ

A carbide sizer sizes the cartridge while it is being crimped so every round will positvely chamber freely with factory like dependability. The adjusting screw quickly and easily sets the desired amount of crimp. It is impossible to buckle the case as with a conventional bullet seating die. Trim length is not critical so this extra operation takes less time than it would if cases were trimmed and chamfered.

Revolver dies roll crimp with no limit as to the amount. A perfect taper crimp is applied to auto-loader rounds. The crimper cannot be misadjusted to make a case mouth too small to properly head-space. A firm crimp is essential for dependable and accurate ammunition. It eliminates the problems of poor ignition of slow burning magnum powders.

[Delmonico]

To put it in simple terms, the taper crimp which the Lee Factory crimp for straight sided cases is a form of, (The one for bottle necks are a different animal that uses a collect) keep the sides from bulging out if you try to crimp a slightly too long case.  It also will roll the case neck into the crimp groove if their is one present. 

In fact if anyone wants to experiment you'll find a good heavy taper crimp will hold the bullet tighter in the case than a roll crimp and that what we want in the first place.

[Shotgun Franklin]

Last month while cleaning I discovered 350 bullets. They are 225 gr lead with a flat nose and no crimping grove. I'm fairly sure they are for a .45 ACP. I loaded them over 8.2 gr of Unique using a WW Primer, not recommending this just reporting. This is hotter than most folks would load for SASS but not as hot as I use normally. I used a Taper Crimp. I shot 50 rounds checking to make sure the bu8llet remained in its original position in the case. Every round shot fine and not one bullet moved in the case until fired. I'm just reporting what happened, make what of it you want.