Roll crimp or taper crimp .45 ACP

[DMY]

My S&W 625-2 is chambered for .45 Auto Rim, but can also use .45 ACP with half moon or full moon clips. I purchased RCBS dies for each cartridge. The Auto Rim seating die implements a roll crimp, which I presume is standard for revolver cartridges. The ACP seating die implements a taper crimp and I also have a separate Redding taper crimp die which I recently purchased.

My questions are:
1. If I am reloading ACP rounds to use in the revolver, can I use a roll crimp?

2. If I can use a roll crimp for ACP rounds for my revolver, should I use a roll crimp?

I only use light target range loads, so I presume excessive pressure is not a concern. I have only used taper crimped ACP cartridges and roll crimped Auto Rim cartridges so far. However, since I was recently able to hone my full moon clips to function reliably, I noticed that the taper crimp hangs up a little on my non-chamferred cylinder. I am only putting a light taper crimp on the ACP rounds, enough to pass the plunk test.

 

[schmellba99]

For a revolver, it really doesn't matter because you are using the half moon to keep the rounds in place during shooting. Whichever works best for you, though I pretty much adhere to the "autos get taper, revolvers get roll" with every round I load just to keep things uniform across the board.

 

[Nick_C_S]

1. If I am reloading ACP rounds to use in the revolver, can I use a roll crimp?

If it is a bullet with a cannelure or crimp groove, yes (these are usually revolver-purposed designed bullets). But it's optional - especially in your situation (heavy gun, light loads).

2. If I can use a roll crimp for ACP rounds for my revolver, should I use a roll crimp?

Not necessarily. If you're loading, say, your basic 230gn RN FMJ with no cannelure, it's probably best to use a taper crimp. i.e., if it's a semi-auto purposed bullet, then it's probably best to taper crimp it. Especially if it's a plated bullet, you don't want to roll crimp it and dig into that thin plating. If it's copper jacketed, then it's an either/or situation. But again, in a light recoil situation, I'd recommend just going with a taper crimp.

At least, that's how I see it. And, that's how I do it for my 38 Special ammo. I load a good amount of plated bullets, and taper crimp them. Then I have a good amount of lead bullets with a crimp groove; and I taper crimp some (light recoil), and roll crimp others (heavier recoil).

 

[DaleA]

For .45 ACP taper crimp.

Even if you don't have a semi-auto, who knows, one might just captivate you and then you'll want to have non-roll crimped .45 ACP.

 

[Ozzieman]

Taper, takes away the issue of different case length. Also allows a good crimp without deforming the bullet.

 

[hartcreek]

I roll crimp everything. I have no control over what gun someone will use to shoot ammo that I have loaded and I want no set back problems. Just because a cartridge headspaces on the case mouth does not mean that you can not use a roll crimp. You just have to find the balance between having enough crimp and still having proper headspace.....it aint that hard.

 

[Jim243]

If your concern is that the bullet will move forward (all non-crimped revolver bullets will) then a roll crimp for revolver bullets will insure they stay in place. It will deform the bullet slightly, but do not worry the forcing cone on the revolver will take care of that. If however, you will be using the same load for a semi-auto, I would recommend that no crimp is used and that you segregate (separate) those used for revolver and semi-auto.

If you are using bullets with a cannelure then a roll crimp into the cannelure will work best in both a revolver as well as a semi-auto.

Hope this helps.
Jim

 

[TimSr]

Answer is, either one is correct for a revolver. I would let the bullet being used determine what type crimp. If it has a cannelure, role crimp, if not - taper crimp.

 

[gunfighter48]

Answer is, either one is correct for a revolver. I would let the bullet being used determine what type crimp. If it has a cannelure, role crimp, if not - taper crimp

This is not true for all revolvers. I have a Ruger New Blackhawk 45ACP/45 Colt convertible. The 45ACP cylinder is made to space on the case mouth the same as semi-auto 45ACPs. If you roll crimp the 45ACP it may not space correctly in the cylinder. Not something you would want to happen. All the 45ACPs I have ever seen are taper crimped only. I have not used moon clips with 45ACPs so don't know if that would make a difference as to the crimp method.

 

[hartcreek]

Use your calipers and measure your roll crimps. All it takes is one or two thousands of an inch of a roll crimp to hold the bullet in place with case mouthed brass.

Speer Reloading Manual 11

Page 434

Since the 45 Auto headspaces on the case mouth, only a slight taper crimp can be used. Most guns also work well when the ammunition has a slight roll crimp.

 

[James K]

You should use a taper crimp for .45 ACP. The reason is that a rolled over case mouth does not offer solid enough case support for good ignition and that can affect accuracy and even cause misfires. It is true that the case is supported by the clip, but it is too springy to offer as good support as a firm seating on the case mouth.

The .45 Auto Rim, of course, is supported by the rim and either type of crimp can be used as long as it is enough to retain the bullet against recoil.

Jim