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Discussion Starter · #1 ·
Can someone explain the difference to me?

I currently have the Hornady .357/.38 dies which I am using for .38. The crimp on the seating die does not reach the .38 rounds. I started looking at dedicated crimp dies, but cannot understand fully which one would be better for me. For now, my .38 rounds will be fired out of revolvers only, with a .356/.38 rifle hopefully in my future (not soon though). Thanks.
 

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I am not a pistol shooter. In general, taper crimp is for calibers where round is headspaced on case's mouth. Roll crimp is for revolver ammo, where headspace is on the rim of the case. I am sure there are exceptions and nuances.
 

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RCBS and Hornady are very high quality reloading gear manufacturers. I've standardized on RCBS for my main purchases. I've used Hornady gear and consider it on par with RCBS. Both good stuff.

An ancient wise old reloader told me to not rely on my RCBS crimps for my ammo (roll or taper). During the combined bullet seating/crimping process sometimes the cases get smooshed and are then not to dimensional specification. (Potential feed problems.) Near dimensional perfection is imperative for semi-automatic loading firearms. From RCBS dies I have also seen case mouths botched when the RCBS seating die was making roll crimps on .30-.30.

Lee Carbide Factory Crimp Dies were recommended to me:
Lee Carbide Factory Crimp Die - Lee Precision

I seat my bullets w/my RCBS but do not crimp them. I final crimp (extra step) with the Lee dies. All my feed problems have gone away.

All my roll crimp ammo and taper crimp ammo is final crimped with Lee. I even use Lee crimps w/my lever guns (.30-30, .35Rem, and .444).

The threads w/Lee and RCBS are compatible. Threaded Hornady dies and RCBS dies are also compatible. So Lee should be GTG in a threaded Hornady set up.
 

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The taper crimp is put by the tension applied all around. In other words the die compresses the walls of the brass to increase tension.
The roll crimp is a way to force the mouth of the brass to bite a bit into the projectile. Might have an additional ring below to work as
a stop for the bullet.
Both methods can go together. Not really necessary for revolvers but it might be a good thing with autoloaders and defensive ammo.
the thing with the roll crimp in rimless cases is that it has to be shallow because the autloader headspaces on the mouth/edge of the
brass. this is to give extra assurance to prevent bullet set back. Look closely at defensive ammo you will see 2 crimps and in some
an additonal ring below according to the bullet length. Those rounds drop perfectly snug in the barrel.
When reloding for pistol everyone shoudl take the barrel out and make sure the final setting of the round drops w/o problems in the
chamber. Once you are setup just repeat and re check from time to time. consistency is the key in reloading.

 

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Needless to say rimless cartriges with a bottle neck like the 357 SIG can have as much crimp on the canelure as needed because
they headspace from the shoulder as most rifle rounds do. So they have both roll and taper/tension to set the round.

 

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Discussion Starter · #6 ·
Thank you for the explanations! I'll probably pick up the Lee die next week. Now I loaded some .38 with NO crimp recently. Safe to shoot?
 

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Thank you for the explanations! I'll probably pick up the Lee die next week. Now I loaded some .38 with NO crimp recently. Safe to shoot?
I guess there is enough tension in the case to hold the bullets right? so assuming all other things are fine in a revolver this is not an issue.
I only would be worry if you shoot from a magazine or tube feed rifle. makes sense?
 

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Discussion Starter · #8 ·
Because the bullets will push in on each other, seating the bullets deeper than intended. Correct?
 

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Because the bullets will push in on each other, seating the bullets deeper than intended. Correct?
Autoloading or loading from a mag on a swift move requires a violent action so you want to make sure the projectiles stay put and do not go into the case
creating jams and/or a potentially dangerous situation.
Also on a lever tube magazine the bullets ram each other with recoil.
So for any purposes other than target form a revolver it is better to have them roll and/or tapered crimped depending on the firearm and use.
For hunting I have all crimped and weather sealed in case the bullets fall in the water or what not.
I also test ammo in the barrel before I take it on a hunt. last thing you want to find out they do not cycle ok when you are presented with a shot.
In average is good to prepare the rounds with the same finishing method, measures and routine. Repeatability and consistency is the key.
 

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For a round like 38spl/357mag that headspaces on the rim, I would suggest that if you have just one crimper that it be a taper. You can still apply a taper crimp to a bullet with a cannelure to prevent setback, but you can also taper crimp non-cannelure bullets like plated to get a consistent pressure.

About the only thing I think a taper crimp cannot do that a roll crimp can do is set a deep crimp into the crimp groove of a bullet loaded over a low powder charge in a target round. You can load 38spl way down with lead bullets, and getting a deep crimp can help with getting consistent start pressures which can help accuracy in those mousefart loads.
 
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