.45 ACP Only Works in One Pistol

[Swifty Morgan]

Interesting thing happened today.

I made a bunch of .45 ACP ammo. I made lead rounds with Zero bullets, and I made defensive rounds with Hornady XTP's and new brass. When I made the ammunition, I kept a .45 barrel by the press, and from time to time, I checked to see if the rounds would drop into the chamber. They did.

Today I shot a gun with a different barrel, and the Zero ammo did not want to go into battery. The slide kept sticking about 1/8" back. I was able to push the slide forward when this happened, so the ammunition was usable, but it turned a semiauto pistol into something more like a bolt action.

When I made this stuff, I tried not to crimp any farther back than I had to, because over-crimping can make the case too wide. It looks like I went too far in the other direction.

So. Does this happen to other people? Should I have been using a caliper or micrometer instead of a barrel to check the mouth width?

The XTP ammo shot just fine.

[mikejonestkd]

If my memory serves me the case diameter should be .471-.472" at the case mouth when loaded with lead bullets. Check your crimp, it may be too light.

[PolarFBear]

I've experienced similar failure to close to battery. Found some of my cases were just "slightly" bulged at the base. I used the Lee Bulge Buster from then on. I've also had occassion where a nick on the case rim would stop the round from fully chambering. Used a little file on those but implementing the Lee B/B took care of it after I started using it. I load for lots of chambers in the same caliber. I now use a case gage on every one. It also gives me a chance for a final quality control check.

[Swifty Morgan]

If I understand SAAMI's material, the drawing says 0.473" at the mouth. I didn't use a caliper because it seemed like it would be hard to get an accurate measurement on something tapered, and I figured an actual chamber would be the best tool to prove the rounds worked. I didn't consider the possibility that one chamber would be tighter than another. I should have thought about it, because I already knew I had a Storm Lake Glock barrel that wouldn't accept everything the OEM barrel did.

I guess I'll have to save this ammo for the gun it fits and get a case gage.

[zeke]

Not all chambers are cut the same. Another possibility is if you set the col by testing into a long throat chamber, it may not fit in a short throat (leade) chamber. Especially with wider dia bullets. If wanting to have your loads fit all your pistols, set the reloading procedure to fit the tightest chambered one.

[Swifty Morgan]

I just ordered 5 gages. Hopefully this will solve the problem.

[Aguila Blanca]

Originally Posted by Swifty Morgan

If I understand SAAMI's material, the drawing says 0.473" at the mouth. I didn't use a caliper because it seemed like it would be hard to get an accurate measurement on something tapered, and I figured an actual chamber would be the best tool to prove the rounds worked. I didn't consider the possibility that one chamber would be tighter than another.

It's not just "tight" chambers you need to be concerned with. There's also the question of bullet/cartridge length and freebore, or leade.

In a semi-auto, the cartridge is located (headspaced) in the chamber by the mouth of the case coming to a hard stop against a shoulder at the forward end of the chamber. This means the bullet protrudes into the barrel. We don't want the bullet to engage the rifling before it starts moving, so the first portion of the barrel is reamed to remove the lands, leaving a smooth bore for the bullet to fit into. This is referred to as freebore, or leade.

Different barrel makers may ream to a different length of freebore. For all I know, different reamers with the same factory may produce slightly different lengths of freebore. I have had guns that refused to chamber multiple brands of factory ammunition due to insufficient freebore.

That's a long-winded way of saying that your problem may be due to the crimp, as you surmise, but it could also be that you have a bullet with a "fat" ogive profile and a barrel with a short freebore.

[44 AMP]

I just ordered 5 gages. Hopefully this will solve the problem.

Or maybe you just ordered some stuff you don't need, though it might be useful.

Here's the thing, the "plunk" test isn't to ensure your ammo will go in A .45acp barrel, its supposed to be THE .45 barrel you will be shooting them from.

All barrels aren't the same, aside from manufacturing variations, there are also differences in "throat" length.

any chance you didn't shoot all those Zero rounds that you had to push the slide closed on??

Any chance you ejected one of those rounds, unfired, so you could look at it and try and figure out what the problem was??? You should have.

Its not impossible that the barrel in the gun that wouldn't shut all the way had the bullet entering the rifling, and you pushing it shut just shoved it in a little deeper. Not usually a problem, with lead bullets but a potential one, always.

If you had stopped and ejected a round the 2nd or 3rd time it happened you might have seen rifling marks on the bullet, which would tell you exactly what's going on.

Unless someone is shooting at you, its never a bad idea to STOP when the gun doesn't work exactly as expected, and figure out why, before going on.

And, like a lot of things, thinking you know what's going on, and knowing what's going on can be different things.

[Swifty Morgan]

I have lots of rounds just waiting to be analyzed. No shortage at all.

I can try chambering and ejecting one to see what happens. I didn't see any rifling marks when I checked them in the pasture, but I wasn't wearing reading glasses

[Mike38]

Today I shot a gun with a different barrel, and the Zero ammo did not want to go into battery. The slide kept sticking about 1/8" back. I was able to push the slide forward when this happened, so the ammunition was usable, but it turned a semiauto pistol into something more like a bolt action.

I have a M1911 with a Kart barrel that has a tight chamber. The only way I can get my reloads to work in it is to finish the reloading process with a Lee Factory Crimp die. It "irons out" any bulges in the case wall OD, and puts a nicer crimp on the case mouth. Much better crimp than the seating/crimp die puts on it. If I don't use the LFC die, the slide occasionally stops about 1/8" short, just like what you are experiencing.

[std7mag]

Swifty,
Return the 5 gages you ordered. You just wasted your money.

Your COAL is too long. This becomes more of an issue with lead bullets vs jacketed.
Use the barrel from the pistol that won't go into battery, and use that for your plunk test from now on.

Oh, and if your near max charge weight, drop that down accordingly too!

[Don P]

I didn't use a caliper because it seemed like it would be hard to get an accurate measurement on something tapered

Untrue. you are only measuring the case at it's mouth

[pete2]

I have had to adjust seating depth because of a bbl with no leade or a short leade. The ammo worked in 5 of 6 pistols but not in a Ruger CMD. I only had to shorten it about .004" to get it to work. Use the bbl out of the gun that is not working to adjust the length of the round. You may also run into some small or min. chambers. My 625 revolver won't accept 45 rounds unless they are pretty close to factory dimensions. All my 1911 guns are a little oversize as far as diameter is concerned. I load for the gun with the tightest and the gun with the shortest chamber. My ammo will now work in all 7 guns. (diameter that will fit the 625, length that works in the CMD).

[Jim Watson]

What lead bullet from Zero?
What OAL?
What length head to shoulder if SWC?

Five gauges? I have two because it turned out that one is a case gauge with no throat or leade like a gun barrel.

[Swifty Morgan]

Untrue. you are only measuring the case at it's mouth

If the mouth is wider than the rest of the casing, a caliper (which only non-machinists think of as a precise tool) will find two good points to rest on. If it's not, you can get a deceptively large value because your calipers will rest somewhere behind the mouth.

SAAMI says the rear of a .45 ACP cartridge is wider than the mouth.

I think I should have used the caliper anyway, because even though it's sloppy, it seems to work fine for other people. As a machinist, I can't get used to the fact that people really try to take precise measurements with dial calipers. No machinist does that.

[Aguila Blanca]

If the mouth is wider than the rest of the casing, a caliper (which only non-machinists think of as a precise tool) will find two good points to rest on. If it's not, you can get a deceptively large value because your calipers will rest somewhere behind the mouth.

SAAMI says the rear of a .45 ACP cartridge is wider than the mouth.

That's what their cartridge drawing says, but in the real world the forward part of the case is almost always swelled a few thousandths to the depth of the bullet.

I think I should have used the caliper anyway, because even though it's sloppy, it seems to work fine for other people. As a machinist, I can't get used to the fact that people really try to take precise measurements with dial calipers. No machinist does that.

I would tell that to the guy who owned the machine shop down the road from me, but he retired a few years ago. I watched him use a dial caliper innumerable times -- can't remember even seeing an actual micrometer. If the caliper is accurate to 1/1000 and the micrometer is accurate to 1/1000 ... please explain why the micrometer is golden, and the caliper is verbotten?

I didn't use a caliper because it seemed like it would be hard to get an accurate measurement on something tapered, ...

Did it not occur to you to hold the caliper jaws perpendicular to the long axis of the cartridge rather than parallel to the long axis?

[44 AMP]

As a machinist, I can't get used to the fact that people really try to take precise measurements with dial calipers. No machinist does that.

What do you use??

Maybe today a dial is passe` is digital really better??

In my day, we used Vernier calipers, which actually require a degree of skill to read accurately, BUT a skilled user could read down to half the graduations on the Vernier.

[higgite]

If the mouth is wider than the rest of the casing, a caliper (which only non-machinists think of as a precise tool) will find two good points to rest on. If it's not, you can get a deceptively large value because your calipers will rest somewhere behind the mouth.

Yes, but in the first 1/4” from the case mouth, there is only .0002” difference in the SAAMI case diameter. Your calipers most likely can’t see that difference. If you taper crimped properly, the part that you're measuring will, for all practical purposes, be straight walled anyway.

SAAMI says the rear of a .45 ACP cartridge is wider than the mouth.

See above.

[mehavey]

can't get used to the fact that people really try to take precise
measurements with dial calipers. No machinist does that.

Dial calipers are easily good to a thousandth -- and interpolable to 10 thousandths.
(how do you think we got to the Moon?)

(a .264 bullet)

As far as the rest of the issue goes, if you smoothly taper crimp (i.e., 45 ACP die) the mouth to 0.471" the rest of the case is proportionally sized as well.

Get a set of calipers of whatever version you want ... and get real friendly with them.

[Swifty Morgan]

If the caliper is accurate to 1/1000 and the micrometer is accurate to 1/1000 ... please explain why the micrometer is golden, and the caliper is verbotten?

The fact that an instrument has 1/1000" graduations doesn't mean it's accurate to 0.001". Machinists use calipers all the time for work with big tolerances, but if you really want to be within a thousandth, you use a micrometer.

Calipers will generally give you different readings depending on how you close them. Most people don't even know the proper way.

It's a quick tool for quick measurements. Very useful, but not trustworthy for repeating precise values.

It's very hard to convince non-machinists of this, however. Or even machinists who aren't used to doing precise work.

[mehavey]

...quick tool for quick measurements

which is precisely what you needed, and needed to use, and accurate/repeatable to 3(+) decimal places.

You don't need any more gauges for ammunition purposes.

[pete2]

Dial calipers are adequate for most reloading purposes. Don't believe me? Compare the readings with a micrometer. The readings will be awfully close. I have both tools and usually use the calipers after comparing them.

[Aguila Blanca]

I have four dial calipers, one digital caliper, an analog micrometer and a digital micrometer. (Not counting the tube micrometer, the inside micrometer, and two depth micrometers). For reloading (and pretty much all gunsmithing work) I use one of the dial calipers. It's far easier to zero as the temperature changes, and more than accurate enough for reloading.

[Mike38]

How do you measure the crimp on a case mouth with a micrometer? A caliper has the "knife edge" tip to measure a case mouth. A micrometer would be like using a tree stump in comparison.

[Unclenick]

You gently use the edge of the "stump" or you buy a blade micrometer.