View Full Version : 45 ACP Min Case length

March 1, 2011, 06:05 AM
What is the minimum size case that will still work effectively? I'm new to reloading 45ACP and still used to the 30-06 stretching every time.

March 1, 2011, 10:28 AM
Your loading manual should give you that on the fist page of each rounds load data.

My Speer manual says trim length for .45 ACP is 0.888 max is 0.898. My Hornady manual says its 0.893 and 0.898.

With straight walled pistol brass, I never check OAL, and shoot/load them until the case fails, which is usually a split neck. Its also usually a good long time before that ever happens too. Literally years of constant use in most cases.

March 1, 2011, 04:36 PM
Thanks, I'm using a Sierra Bullets Reloading Manual "Second Edition" It doesn't have minimum case length for any cartridges. Like I said, I've never been able to load without trimming and I appreciate the help. I have some cases as short as .893 and I'll give them a shot.

March 1, 2011, 04:53 PM
Reloading pistol is a bit easier than rifle. You dont normally have the case worries and work like you do with rifle brass. Its also longer lived.

You may want to upgrade your manual. I think Sierra is up to its 5th edition now.

What kind of bullets are you using and what were you thinking for a load?

March 1, 2011, 05:01 PM
I'm waiting for my Midway shipment of 185 grain Nosler JHP's and was going to start out with 5.4 grains of Win 231 with Win primers. If they get here soon I'll be at the range this Saturday with the trial batch. Also trying out my new Bersa Thunder if I don't blow my hand off.

If all works well I'll be ordering some cheap lead bullets, I just want to get the mechanics worked out first.

March 1, 2011, 05:27 PM
Blowing your gun up and your hand off wouldnt be a good start. :)

Lead is definitely cheaper. I usually use 200 grain LSWC's with either 231 or Universal.

Jim Watson
March 1, 2011, 05:48 PM
Straight cylindrical pistol cases can actually shorten with use as they expand to fit the chamber. Trimming is not normally required, I think I have seen three over-length .45 ACPs in only 40 years of handloading. And they all came along the same season with the same headstamp, probably one out of spec box sold here.

maggys drawers
March 1, 2011, 06:18 PM
M.L. McPherson Metallic Cartridge Reloading 3rd. edition:

45 ACP Minimum Case Length: 0.898 inches.

March 1, 2011, 07:02 PM
You do not need to trim straight wall semi-auto pistol cases. They actually get shorter by a minuscule amount each time they are resized.

March 3, 2011, 10:18 AM
M.L. McPherson Metallic Cartridge Reloading 3rd. edition:

45 ACP Minimum Case Length: 0.898 inches.

Should that not beMax Case Length ?

March 3, 2011, 01:07 PM
In most manuals the trim to length is the minimum case length.
Lyman lists 45 ACP trim to (min) as 0.888, and max as 0.898

March 3, 2011, 02:22 PM
As Jim Watson said, these cases, as well as most others running below around 30,000 psi, will shorten with use. I tracked this once with a lot of Winchester cases that I reloaded 50 times with light lead bullet target loads. They were 0.025" shorter by the end of that experiment and still working.

The SAAMI specification, as someone else mentioned, is 0.898" +0.000"/-0.010". In other words, 0.888" to 0.898". However, only the maximum is critical to safety, while the minimum is more like a suggestion. The minimum is what bullet makers need in order to put a crimp cannelure in the right place and for cartridge makers to keep a single crimp die setting. If you use lead bullets and a taper crimp die, you can just keep the same COL, but adjust the crimp die down a little as cases shorten.

March 3, 2011, 03:12 PM
The only change in size on my oldest 45 brass has been to the diameter of the rim from pounding into the breach face. After dozens of reloading cycles some of my cases won't fit into the shell holder on my press. Sometimes I can twist them back and forth and get them to slide in. These are normally some of my 20 year old cases, soon to be regulated to throw away hunting brass. Otherwise I wait until I get a split case mouth to toss the brass.

March 5, 2011, 08:58 AM
Unclenick, doesn't the .45 ACP head space off the front of the case? If it does, wouldn't making the case too short result in problems getting a proper hit on the primer and maybe extraction problems? Of course it would probably take more than a few thousandths but I would think there is some point that too short would cause a problem. As I'm a newbie to .45 ACP I'm just asking, not disputing.

March 5, 2011, 11:38 AM

Chamber tolerances in the ubiquitous 1911's and in many other .45 ACP's get's pretty loose. I've seen estimates by a couple of smiths who see a lot of them that probably half or more of what comes to them are actually headspacing on the extractor hook even with new factory ammo. In other words, the extractor hook stops the cartridge moving forward before the case mouth gets to the lip of the chamber throat. Even if the barrel chamber is cut to spec, there is often enough space left between the back of the barrel and the breechface in the slide that the total headspace is out of spec.

Good extractors seem to put up with that. For lead bullet accuracy this is a poor situation, though, as the cartridge tips to the side of the chamber at firing and lead bullets aren't hard enough to straighten themselves out entering the throat. As a result, they are swaged into the bore at a slight angle, shaving some lead off on that lip, sending an asymmetric bullet mass down range and also increasing bore leading.

For lead bullets, target shooters, even going back to the 50's and 60's, switched to headspacing on the bullet. Lots of the old timers found they got much better consistency putting a significant roll crimp on the rounds to improve start pressure by stopping the primer from unseating the bullet before the powder burn got under way. In order for that roll crimp not to jam into the throat and cause a pressure hazard, the bullet had to be seated out far enough to meet the throat before the crimped case mouth went that far forward.

The problem with the roll crimping, as anyone reloading for revolver (where a roll crimp is usually required) can tell you is that case life is shortened and case mouth splits start before long. Mostly we use taper crimps in self-loaders these days in order to prevent that, but it won't stop primer pressure unseating of a bullet. Using hard cast bullets and headspacing on the bullet even earlier seems to help this situation. It improves accuracy, often significantly, and reduces leading. You just have to use a bullet shape stubby enough to seat out that far an still feed from the magazine OK.


March 6, 2011, 08:39 AM
Lots of good info there. I just checked my Springfield Mil-Spec. With Federal AE the case is about .012 below the breach face. Case is .892. I checked a handful of once fired mixed brass and .891-893 seems the norm. One out of ten was .889.

If I understand you correctly, you are suggesting that the bullet be seated far enough out so it just contacts the rifling. Yes?

March 8, 2011, 12:01 PM
I am suggesting lead (and plated) bullets be seated that way. Lead bullets not only need to enter the throat straight to remain accurate, but they are soft enough that if your press lets a round come out a few thousandths long, the gun will still close on them by forcing them into the throat.

Jacketed bullets don't seem to benefit from the special treatment, so I just seat them for most reliable feed. Lead bullets are soft enough to be prone to being distorted if they are driven into the throat if that event commences with the round pivoted to the side of the chamber against the extractor hook. Jacketed bullets straighten themselves out in the throat without damage.