Resizing 45 ACP

[308Jeff]

Looking at my load log, I've only loaded a total of 19 rounds of 45 ACP in the last 10 years.

Got the LNL AP set up this morning to start decapping/resizing some brass and came across something that raised my eyebrow.

Some of the brass had already been deprimed (and possibly resized). I grabbed my Lyman case gauge and, the ones that are decapped fell right in. So did the ones that aren't decapped.

I grabbed a box of factory ammo and dropped a round in the case gauge. Plunked right in there, but I decided to try to give it a wiggle to see if maybe the gauge is "generous". It did wiggle, quite a bit.

Next thing I did was grab my XD and pull the barrel. Dropped the factory round in there, plunk, lots of wiggle. Grabbed a piece of the unsized brass, plunked right into the barrel, as did the next 10 pieces I tried. They all went in fairly easy, except one that I easily pushed in and pushed right back out.

I don't remember where I got this brass, it's all nickel. Probably from Gun Broker.

So what's the deal with 45 ACP? Why so much play/slop in both the gauge and my pistol's chamber with resized brass and factory ammo? I assume that has to be normal, and by design?

[BK7saum]

The case gauge should be slightly smaller than the chamber, i.e. SAAMI minimum, to allow for all ammo that passes the gauge to chamber in all firearms of that caliber. Resize dies are smaller to make sure that all brass, even the very thinnest creates enough neck tension to hold a bullet.

So you end up with a loose fit to allow for a dirty chamber and ammo to fit in any chamber out there.

[Scharfschuetze]

All of the above. Also the 45 ACP is a very low pressure round compared to the 9mm or other hot rods for pistols. Given that, case expansion after a shot is not as pronounced as in higher pressure rounds. It certainly is enough, particularly with large chambers, to need resizing.

[308Jeff]

All of the above. Also the 45 ACP is a very low pressure round compared to the 9mm or other hot rods for pistols. Given that, case expansion after a shot is not as pronounced as in higher pressure rounds. It certainly is enough, particularly with large chambers, to need resizing.

That makes sense.

I've never had an unsized 9mm or 40 S&W piece of brass that would drop in the case gauge or a chamber, it surprised me that 45 would.

Now I know why. :-)

Thank you!

[oldhenry]

When you seat the boolit (assuming a .452 dia.) more than likely the OS dia. of the loaded round will be slightly larger than the resized empty case.

[tazman]

This link was provided to me by Bullwolf. I found it very informative in regards to reloading 45ACP. While not addressing the need to resize directly, it does talk about case length and other case size issues as you reload over time.

http://www.massreloading.com/loading45ACP.html

[308Jeff]

Great read, tazman. Thank you!

[JBinMN]

Great read, tazman. Thank you!

Ditto! and bookmarked for others to see in the future. I know some others who would love to read it.
:)

:drinks:

[Bzcraig]

Great read Tazman! It was like reading a 'teaser!' I now will follow this to get answers to the questions at the end.

[Scharfschuetze]

Thanks Taz.

I have GI cases that I've been reloading for decades, so perhaps it's time to DX 'em and start over. Well, maybe I should just save 'em and use 'em in my 1917 revolvers. They should last another couple of decades longer that way.