[redactor]

I am new to reloading and am wondering, do I really need to crimp my .45 Auto rounds? The test batches that I have done seem to work fine without any crimp, unless I'm missing something.

[Jim Watson]

A taper crimp, even just enough to eliminate the bullet seating flare can help in feeding.

[GCW5]

I'm guessing that your dies are putting a taper crimp on your bullets, even if you don't notice it. I have RCBS dies that put a very nice crimp without the need to go to the extra step of putting a seperate die in to do it. I have a set of Lee dies made to also load 45 auto rim, the put a roll crimp on the cases, so I need to use the Lee taper crimp die with them.

You'll need atleast some crimp to feed, since you expanded the case neck to start the bullet. Since rimless cases headspace on the case, it's not good to use a roll crimp on rimless cases. A taper crimp allows the case neck to be outside the bullet enough to headspace, yet holds the bullet tight enough that it dosnt move in the magazine during fireing.

Hope this helps.

[The Bushmaster]

Lee? .45 ACP seating and crimping die has a roll crimp? No...Mine don't. They have a taper crimp. All you need to do is remove the bell anyway. Like GCW5 says...You are probably removing the bell and don't know it.

[FieroCDSP]

THe other two gave good info on how to do it, but your question is whether it's necessary. IMO, yes, you should give all bullets some form of crimp. Bullet set-back is the issue here, and the 45Auto has more than enough power to cause it to happen. Should the bullets have a setback of .001", it probably won't matter, even with max loads. If it moves back further, say .010, that is more than enough to over-pressure a max-load, and that ain't good. Even a light taper crimp is better than none.

[The Bushmaster]

And the low pressure of the .45 ACP probably will not cause a set back. Besides the bullet to case friction is enough to not allow this to happen. Look at the finished cartridge and you will notice the bulge (case expantion) the bullet caused when you seated it...Just remove the bell. I never did for 18 years and never had a set back with my .45 ACP and I load hot. Just started removing the bell just because....:D

[redactor]

I'm using Redding dies, and I followed the included instructions for no crimp.

[Deanimator]

It depends upon what you mean by "crimping". There are two kinds.

Roll crimping is what you do with a revolver round to ensure that the bullet doesn't back out of the case under recoil and tie up the cylinder. This is NOT a good idea for semi-auto cartridges since most headspace on the case mouth.

Taper crimping squeezes the case down onto the bullet without rolling the mouth of the case over. This allows the cartridge to headspace properly on the case mouth. Crimp to the case diameter recommended by your reloading manual.

I recommend that you get [if you don't already have] a taper crimp die, and seat and crimp separately. It's how I do all of my .45acp on my Dillon and I get excellent ammunition.

[GCW5]

Gee Bushmaster, I didn't know Lee made 45 dies that didn't roll crimp. I bought mine about 20 years ago when I bought my .45 auto pistol, they say right on them for .45 auto & auto rim. I had to buy a taper crimp die to use them. I was pretty PO'd about it at the time, because $ was short, and I was trying to save a little by buying the Lee dies instead of RCBS. By the time I had the extra die, I had more rapped up in them than the higher die set. They always worked well, I just had to do the extra step. I bought a set of RCBS dies a couple years ago used, they seat and crimp in one pull, I've used them pretty much since. I keep the Lee's around, hopping to need them on the 625 I plan to get when I find for the right price.

[Stinger]

A crimp is not needed with the 45acp.

Certainly, a roll crimp should not be used on a cartridge that headspaces on the mouth, like the 45acp. So if you must crimp, do as the other suggested, and taper crimp only.

[The Bushmaster]

Still have the instruction sheet that came with my Lee .45 ACP die set. And it states nothing about a roll crimp. But does state..."If a crimp is desired, screw the die in slightly and test until the proper crimp is formed". I will take it upon myself to research this farther just to satisfy all...:scrutiny:

[The Bushmaster]

GCW5...I just got off the phone with Lee Precision Inc. Mine and all other Lee .45 ACP/Auto Rim dies utilize a TAPER crimp. No matter the age of the die set...A TAPER crimp...:scrutiny:

[BigG]

I think the term "crimp" is a misnomer as applied to 45 ACP in this thread.

The 45 ACP case mouth is belled in a step prior to seating the bullet. When the bullet is seated, the die automatically restores the outside diameter of the case mouth to its original size; in other words the die irons out the case mouth, restoring the case to a cylindrical shape. There is no crimp about it or it would not headspace on the case mouth as designed.

A revolver cartridge is roll crimped at times, the edge of the case actually rolled over the bullet at a place where the bullet is less than full diameter.

The taper crimp idea makes little sense when it means that you are constricting down the case mouth and hence the bullet inside. What do you gain by this process except making it less accurate?

[Jim Watson]

I don't know about YOUR crimp die, but MY crimp die puts a visible and measurable taper to the mouth of the case. It leaves ample case wall thickness showing for headspace control. It also eases my mind about feeding.
The local shop once had some Lawman hardball that would not feed reliably in guns that had been shooting other brands and reloads. It had no taper and a very sharp edge to the mouth of the case. The dealer ordered Remington the next time and all the troubles went away.

I have an old American Rifleman article by pistolsmith Alton Dinan. He recommended a hard roll crimp on .45 ACP ammunition to be shot in his guns and backed it up with machine rest groups and match scores.
Of course that was for semiwadcutters properly seated to headspace with the shoulder against the origin of the rifling.

[Walkalong]

I don't know about YOUR crimp die, but MY crimp die puts a visible and measurable taper to the mouth of the case.

Mine too. You can see the slight angle machined inside of Taper Crimp dies and seaters with Taper Crimp capability.

[BigG]

I guess my 30-40 year old RCBS and LYMAN dies just aren't up to date. ;) They have loaded a bunch of 200 gr LSWC ammo and the 45 ACP loaded with them has a sharply defined case edge that doesn't seem to cause hang ups in my Colts. It also looks like factory hardball, except for the bullet type.

The guy Alton Dinan, has an unorthodox approach. It seems to work for him. Again, when you are an expert, you don't have to follow rules that mere mortals must heed. ;)

[GCW5]

Bushmaster,

Thanks for the information on the Lee dies. Next time I reload, I'll play with the Lee dies again, it's been many years since I tryed crimping with them. I'll tell you that it crimped so hard that it left the mouth rolled into the bullet, just like the crimp on my Lee 38/357 dies. When I backed it off enough to keep it from happening, they wouldn't feed. That's when I bought the taper crimp die, and the crimp with it is just right.

[Jim Watson]

I guess I am going to have to buy a set of Lee or RCBS .45 ACP dies just to see how they work. I cannot visualize how you can apply a taper crimp to a smooth sided bullet in the seating die. It appears to me that the bullet would still be moving downward under the seating plug as the case was moving up, relatively, and being squeezed in the taper. Looks like that would scrape up the side of the bullet.

[The Bushmaster]

I set my Lee .45 ACP seating/crimp die up using a dial indicator caliper. I measure the case after it has been belled. Then seat a bullet and crimp ever so lightly that I have to strain to feel it crimp then measure the case mouth again. After crimping, the case mouth should be .469 to .471. If so...Good to go...:D

I just know someone is going to jump right in there and wonder if I measure each one...NO...Just the first one or two.:scrutiny:

Redactor...Still with us??:)

[Sharps Shooter]

"It appears to me that the bullet would still be moving downward under the seating plug as the case was moving up, relatively, and being squeezed in the taper. Looks like that would scrape up the side of the bullet."

I think there might be some miscommunication here Jim. I always make a "4th" step out of applying the crimp to handgun cartridges. After seating the bullets to the proper depth, I back the seating/crimping die's seating plug out, then screw the die body itself down until I get the desired crimp. The bullets aren't being pushed any deeper into the cases because they no longer come into contact with the seating plug.
However, I'm relatively new also to loading for semi-auto handguns. I'm a lot more experienced with revolver cartridges. And like you, I don't understand how much of a crimp can be applied, regardless of whether it's a roll crimp or a taper crimp, to a case holding a smooth sided bullet (no crimping groove or cannelure) without squeezing the bullet. I guess it's just a matter of applying enough crimp to hold the bullet, but not deform it.:)

[BigG]

There are apparently separate crimp dies included with the newer sets of 45 ACP dies. My three die sets are what I have with no crimp. I screamed 'hallelujah" when I got a 45 ACP carbide sizing die. Now I haven't got the latest and greatest but it still works, A-OK.

With revo ctgs, it is a matter of finding proper seating depth, back out seating plug and screw die body in to make a proper roll crimp, but it must have the groove or smaller diameter. Then you screw down the seating plug to seat to the proper depth and crimp in one step.

I've seen auto pistol rounds with the taper crimp applied but it doesn't look like a quality reloading job to me. YMMV

[Walkalong]

I always taper crimp in a fourth operation. It can be done with the seating die as long as it is not excessive. I just like to do it seperate.:)

There are apparently separate crimp dies included with the newer sets of 45 ACP dies. My three die sets are what I have with no crimp.

I believe all of the 3 die sets have taper crimp ability built in to their seaters.

[Jim Watson]

I know you can dance around with seater-crimper adjustments to seat and crimp in separate steps with the same die. I'd rather have the extra die than mess with all that. I load pistol ammo on progressives with no capability of readjusting the die anyhow.

I am not talking about squeezing the bullet, a pulled bullet that has been through a taper crimp die will show a groove where the case mouth was pressed into the bullet. No way out of it except to not crimp. Lee makes advertising hay out of it in their collet rifle crimp dies.

I am talking about a scrape as the case mouth is pressed in while the bullet is still moving.