.45 ACP: Some Rounds Chamber; Some Rounds Don't

S

Swifty Morgan

New member
Today I was cranking out .45 ACP when I ran out of cleaned, decapped cases. I decided to take apart a few rounds of old ammo which had refused to chamber. I ran them through the press, including the sizing die. They still don't want to chamber.

I then found a box of brass from old reloads. I wanted to finish up my remaining .45 bullets so I could move on to something else, so I sprayed this brass with One Shot and ran it through the press. It does not like to go in the chamber.

The press is set just the way it was for the previous 400 rounds, and they're fine. Same lead, too. The sizing die goes pretty much all the way down to the shell plate, so I don't think it's leaving bulges near the rims.

So. What is causing my problem?
 
The sizing die goes pretty much all the way down to the shell plate, so I don't think it's leaving bulges near the rims.
Click to expand...

The sizing die needs more than "pretty much", it needs to be all the way down and touching the shell holder. After you set the die up to touch the shell holder, when you resize a case in the press, look and see if a space opens up between the die and shell holder with the case up in the die. If so, lower the die a little more.

Don
 
How far do the rounds go into the chamber before they stop?

I would select one round and do a "plunk" test. Remove the barrel from the pistol. Hold the barrel vertically, chamber up, and drop the cartridge into the chamber. It should drop right in, making a characteristic "plunk" sound when the case mouth settles against the shoulder at the end of the chamber.

If a round doesn't drop in cleanly, you need to find out why. (Yes, I know, that's what you're asking). It may not be case sizing. Does your pistol have a short leade? (That's the portion of the barrel from the end of the chamber itself to where the rifling begins.) If you have a barrel with a short leade, and bullets with a "fat" ogive, the bullet may be hitting the rifling before the round can fully chamber. Test for this by taking a round that fails the plunk test and progressively seating the bullet deeper, in increments of .05" or .10" until it either chambers -- or you have drive the bullet so far into the case that you have proved that's not the problem.
 
Thanks for the replies.

It looks like there was a crimp issue. I lowered the crimping die very slightly, and the rounds started going in.

I guess the die must have managed to back out after the last group of cartridges. I made 450 cartridges, and only the last 50, which came from the same box, had this issue.

I didn't think there was any way for the crimping die to move, but it looks like I was wrong about that.

While I was at it, I checked the sizing die, and there was a tiny gap between it and the shell plate, so I fixed that for next time.
 
OP -

With regards to crimping 45s, I apply a case mouth diameter of 0.468". Chambering is consistently smooth and reliable...

Bayou
 
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+1 - "OP -

With regards to crimping 45s, I apply a case mouth diameter of 0.468". Clambering is consistently smooth and reliable...

Bayou"

I found that crimping the case mouth tighter than .470 (.468" - .469") worked with my barrel chambers. I went more fore reliability as Bayou states. No more problems.. even helped SWC in the 1911. :-)
 
Need to define not chambering. They wont chamber at all or wont quite pass the plunk test.
What bullets are you using. This is not uncommon with .452 lead bullets. With the larger diameter of the lead bullet sizing to .468 is tough. Normal case wall thickness is .010. .452 + .010 + .010 = .472. Some brass can have a slightly thicker wall thickness, this added to the extra diameter of a lead bullet can cause chambering issues. It would be worth checking the wall thickness on the cases that don't chamber. It doesent take much to cause an issue. Also, a lot of guns have almost no throat before the rifling. If your OAL is to long a .452 cast bullet (Depending on bullet profile) will hit the rifling and not fully chamber. Check you OAL on the rounds that don't chamber and see if, for some reason they didn't get seated as deep as the rounds that chamber properly.

If you resize brass and it wont chamber with no bullet inserted then disregard the above.

Mike
 
Swifty,

Keep in mind that, unlike rifle cases, the .45 Auto not only does not grow, it shrinks slightly with each reloading cycle. As a result, if you reload the cases many times, they get so short that your crimp die has to be adjusted down. This is one reason I use only relatively young brass for jacketed loads, seating my lead loads out to stop on bullet contact with the chamber throat and don't rely on the case mouth to be able to reach the end of the chamber before the extractor hook catches the rim.

You may want to segregate your cases by length for this reason. You can shoot just the longest ones until they shrink to match the next shorter batch, then combine them. I tracked some Winchester brass through 50 very light target reloadings one time, and they consistently lost half a thousandth with every load cycle.
 
One more thing to consider, about the "plunk test"...
Rounds that pass the plunk test will chamber well

Rounds that ALMOST pass the plunk test but stop short by just a little MAY also chamber properly when the recoil spring driven slide shoves them into the chamber.

You can have a situation where rounds don't quite "plunk" all the way in under gravity but feed and function in the gun during shooting.

just something to consider...

The point about case length is well taken, as well. .45ACP brass does get shorter during loading cycles and while taper crimps are more forgiving about case length than roll crimps, there are still limits, and unusually short cases will require die adjustments to get the desired results.

It's tedious, but measuring and sorting your brass into batches by case length is a good idea.
 
I didn't know the cases could shrink. Let's see. SAAMI specifies 0.898". I wonder how much shorter you can go before you should throw cases out.
 
45 cases shrink and the brass flows downward from repeated re-sizing. After a lot of re-sizing you may be able to see where it actually bulges out after the point on the case where your sizing die reaches. Lee sells a bulge buster to be used in conjunction with it's LFC die which re-sizes the whole length of the case. This usually lengthens the case as well. Some dies size further down the case than others, and a LFC may size down lower than some re-sizing dies. Lyman's carbide dies have a lip below their sizing ring (at least they used to), which can be carefully worked over to provide more re-sizing capability, and it is also possible to shave the top of a shell holder down slightly.

Some wish to put a crimp on to a set diameter, some set the crimp according to what specific brass and bullet they are using. Am preferring to rest my dies each time, instead of trying lock the adjustments in place.
 
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