Tapered Crimp Dies


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ReloaderEd
September 2, 2010, 05:00 PM
Are tapered crimp dies a good thing to use? Also, just how are they adjusted to work? Do all the cases have to be the same length? What brands work the best? Thanks for you imput

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rcmodel
September 2, 2010, 05:09 PM
You don't need to by a separate die.
Almost every set of dies you buy will do either a Taper-crimp, or a Roll-crimp in the seating die, depending on the caliber the dies are for.

Auto pistols use a taper-crimp to straighten the case after it is "belled" for bullet seating.

Revolver calibers do a roll-crimp to hold the bullet in place against recoil.

Rifle caliber use a somewhat different type of roll-crimp that is not nearly as pronounced as a revolver roll-crimp.

You adjust them by following the directions that come with the dies.
Or by measuring the case mouth of auto pistol calibers and comparing it to the Spec drawing in your reloading manual.

Revolver & rifle roll-crimp should be adjusted so the case rolls into the crimp groove or cannelure on the bullet.

Case length is critical on revolver & rifle Roll-crimp.
It is not critical on auto pistol Taper-crimp.

rc

MichaelK
September 2, 2010, 06:46 PM
For fully functional .45 ACP loads, only a real taper crimp worked for me. Tried in vain to get the "modified" taper crimper die of my Lee set to work for me with cast bullets. Just couldn't make it work. A Hornady taper crimp die solved the last of my problems.

What you want is the minimal amount of crimping that will allow flawless functioning. If you have a caliper, measure the case mouth of your cartridge. Compare it to a factory load. It might be a few thousandths larger. You can crimp it to the same diameter as the factory load, or you can let your pistol decide for you.

Take the barrel out of your gun and use it like a cartridge gauge. Drop in a factory round and listen for the light metalic "click" it makes when the mouth hits headspace. You want to make your cartridges do the same "click". Place one of you cartridges into the shellholder and run the ram up to its maximum height. Start screwing down your crimping die untill you start of feel resistance. Lower the ram slightly and screw the die in slightly more. Now, run the ram up again and start crimping. Take your cartridge out, measure it with the caliper, then drop it into the chamber. Just keep on making incremental adjustments to the die till you get the level of crimping that just allows the cartridge to drop into the chamber. Write down that number, lock down the ring, and crimp away. You're done!

ReloaderEd
September 3, 2010, 01:38 AM
Thank you guys. :neener:I really appreciate the help. The imput explains a lot.
My 45acp has had the feed ramp polished and it will feed sized cases not reloaded. So it dosn't take much of a taper crimp just enough to straighten the belled case out. I like the factory round comparison and diameter measurement. thank you..

rcmodel
September 3, 2010, 12:49 PM
Look in your reloading manual for the SAAMI case spec drawing.

It will show you what the max case mouth measurement is.

Your taper crimp should at least match that, or be a couple thousandths smaller at most.

rc

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