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45 ACP Overall Length & Crimps

Date: Sat, 5 Jun 1999 20:39:51 +0800 (GMT)
From: "Dave Salyer" ncfc.4sy@public.nt.js.cn
Subject: Re: .45 OAL & Crimp?

45 ACP OAL has NO effect on accuracy.... and almost no effect on pressure with the 45.

OAL is meaningless unless you know exactly what bullet you are using. (because nose lengths vary all over the map.) What is very meaningful is the exposed shoulder of lead bullet rounds, as this affects the head space. Pistol rounds should not be jammed into the rifling like rifle rounds sometimes are. Take your barrel out and drop your round into the vertical chamber. Adjust its overall length until the case rim falls by gravity just barely beyond flush with the end of the hood of the barrel. Record this setting for each bullet style for future repeatability. Seriously, that is all there is to it. I hope you don't waste valuable time testing as I did before I learned the above. Some less informed people will argue with the above based on invalid testing and what they have read from the writers who don't shoot 45's. I have done extensive testing in a barrel tester and machine rests. Did a little with a bullet (loaded round) tester.

Regarding Zero crimp... This is what the factory Ball rounds are supposed to have. However, it is hard to get perfect zero crimp with reloads. This is due mainly to variations in lead bullet diameters and case thicknesses. Therefore, the tested and true way to make up 45 rounds is to taper crimp the mouth of the case to something between .466 and .470". More crimp than this can cause bullet tumble. If you don't have a micrometer, crimp two rounds and hold them up together toward the light. When it is perfect you will see light between the cases near the crimped edge. the length of this lighted area varies from crimp die to crimp die but should be no more than .100".

Another good test is to use your thumbnail and make sure the edge of the case is buried only half the thickness of the case mouth into the lead bullet.

Loads done this way will feed better than factory wad... and can be just as accurate depending mostly on the pellet quality.

Dave Salyer

Date: Sun, 6 Jun 1999 13:58:15 -0700 (PDT)
From: Ed Harrison deh@atmos.washington.edu

My experience is that accuracy is best when the bullet is as far out as possible and will still feed reliably. If you can get the shoulder to just touch the lands and still get reliable feeding, that is exactly what you want. This is really true for rifles, but also seems so in the tests that my friends have done with handgun ammo.

Also, remember that the front end of the chamber will get crudded up as you shoot, so you will want to load just a little shorter than is possible when the chamber is clean, unless you plan to clean during a match.

I have no doubt that more bad ammo has been made because it was overcrimped than for any other reason. The less crimp the better is my experience. For this reason I use a Lyman "M" die for my long-line ammo; it just opens up the case enough to hand seat the bullet and closes back up beautifully. I seat in one step and crimp in the next. I NEVER use a crimp die that resizes the whole case. I only crimp to .471.

I may be over-doing it. But this works well for me, and I don't shoot enough longline ammo for it to be a burden as far as time goes.

Good shooting to you.

Ed Harrison

From: "Joe Krasnicki" joe.krasnicki@snet.net
Subject: Re: .45 OAL & Crimp?
Date: Thu, 10 Jun 1999 00:19:16 -0400

For a handloader in search of accuracy and reliability in his 1911 for b.e. these steps should be done for every combination of brass or projectile:

for 50yd ammo:(accuracy)
1) take barrel out
2) load a round long and crimp, .471-.472"
3) drop in barrel and observe for bottom of case to be flush/slightly overlength of barrel hood
4) reseat and crimp till reach above

for 25yd ammo:(function)
1) same
2) same,but .469-.470"
3) same,flush/slightly under
4) same

The above assumes the barrel hood was fitted to the slide. Do everything possible to maintain a consistent oal on your 50yd ammo, though it isn't anywhere near as critical for 25yd. In a properly fitted/functioning 1911 the two criteria will merge imperceptably as well as variations in oal.

From: "Joe Krasnicki" joe.krasnicki@snet.net
Subject: Re: .45 OAL & Crimp?
Date: Thu, 10 Jun 1999 21:14:05 -0400

The idea for maximum accuracy is to not deform the bullet. You can measure the thickness of the brass wall, double it, and then add it to the bullet dia.. The rough formula is: i.e. .010" x 2 = .020" + .451(jacketed) = .471. Remington and Federal SWC heads are .452" ,hence .472". This is not written in stone and in some guns the accuracy difference may not be detectable till you overcrimp and deform the front shoulder.

IMO there is no need to crimp any ammo beyond .470 and this is what i use for my 25yd ammo. The reliability issue really isn't related as much to crimp (it really just keeps a slight amount of room in a dirty chamber thats shooting without being able to be immediately cleaned), but the base of the bullet when seated can bulge the brass slightly and that's what causes the majority of failures to chamber providing you've got the OAL set.

.472 is for 50yd ammo where an occasional hiccup won't matter and usually doesn't happen anyhow. I use the Lee factory crimp die that has the carbide sizer for 25yd ammo and it irons out the occasional bumps and guarantees 100% reliability. I use a std Hornady crimp die for 50yd ammo. I also chamber check all ammo and the Lee die returns them all to fac spec so they all check. Frequently many from the std crimp don't check o.k. but function none-the-less.

Factory Federal is sized by roll sizers before and after but you and I don't have these large precision (and high volume) machines. You could simplify and go with one dim for all and just test to be sure.as wel

If I'm loading expensive heads like Rems or Noslers or other match 50yd ammo, the best way to do it is to seat the bullet half way, rotate, then final seat. When taper crimping with the std die, crimp it full on one stroke, rotate then one more full stroke. this sounds like a lot but you'll find the results worth it as these steps guarantee maximum uniformity and concentricity, (at least as good as we handloaders can get). If possible do it on a well mounted single stage press. For my 25yd stuff or practice ammo i crank it out on a progressive.

Date: Sun, 27 Jun 1999 14:39:19 -1000 (HST)
From: "Dave Salyer" ncfc.4sy@public.nt.js.cn

I have done a lot of testing and have found over and over that loading too long, or sometimes even with the hood will cause fliers occasionally. Even with the hood is ok if, you do not have to use finger pressure to press it there in a dirty barrel. Pistol technology is opposite bottle neck rifle technology on this point.

A long chamber or head space clearance does not hurt the .45 at all. I have tested many uncut match barrels. Then retested several after cutting the hood length to fit a pistol and always find no significant difference in accuracy.

Dave

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