32 ACP Actual Diameter

[StevieQuick]

Hey y'all, I've had something I've been wondering, that being is .311 the actual correct diameter for bullets in 32 ACP? I have a .311 mold but I've seen some times where bullets being sold specifically for 32 ACP that are .308 diameter. I've shot such 308 bullets with good success out of my FN1922 but I still figured I would ask what y'all do. Thanks!

[mattw]

We have a member that will chime in, I am sure.... He is a 32 ACP guru. I have a Kel-tec that really likes .311 and does not take heavy high pressure rounds well and I have a CZ0 that wants cast bullets at .312 to .313 and is built to Euro CIP standards and really wants a hotter round to function well. It is really dependent upon who made your gun and when it was made.

Also, not all brass is made to the same standard... some is thin wall and some is very thick. Compare the Euro brass to American brass and you will see the difference. I actually tracked down a Lee undersize size die for some of my brass in order to hold proper tension on a cast bullet.

Slug your bore and it will tell you a bunch about the gun.

32 ACP is a pain it the butt to reload, but they will reward you with good results if you do it properly.

Search the forum here, learn to use google to do a site search. There are many good threads on 32ACP here.

Welcome aboard. Read lots, learn much. Study and verify loads in the tiny rounds as pressure can spike fast and not all guns can take that.

[Thumbcocker]

Groove diameter varies a lot. One Walther i had was .309. My Beretta likes .311.

[Outpost75]

Important in .32 ACP is how large your chamber is in relation to the thickness of the brass you are using. In most cases I would ignore the groove diameter of the barrel entirely and instead determine the largest bullet diameter which will freely chamber when dropping into the barrel of its own weight, and which will fall out likewise.

Problems occur when people use bullets which require greater seating depth than factory FMJ, because the base of the bullet then impinges against the internal case wall where it begin to get thicker towards the mid-part of the case body, so that it causes a bulge, which precludes chambering.

In a tiny case like the .32 ACP deep seating of bullets can also dangerously spike pressure. Accurate has a great variety of well-designed .32 ACP bullets which feed well and approximate both the seating depth and overall cartridge length of factory loads, to positively prevent rimlock, and to ensure reliable feeding.

Many older WW2-era guns will not feed JHPs or flatnosed bullets, but there are a few notable exceptions like the 1935 Berettas and Colt 1903s which will feed nearly anything, even blunt semi-wadcutters with meplats as large as 1/4"!

Groove diameters of .32 ACP pistols run all over the map. Maximum useable bullet diameter is limited more by chamber dimensions and brass body wall thickness than anything else. For the majority of .32 ACPs a .311-.312" diameter works best. Some very tight chambers, such as Keltecs require .309-.310". While some wartime barrels go as large as .315" groove diameter, in a lifetime of fooling with these guns I can count on the fingers of one hand the number of pistols I ever saw which would actually function with a .314" bullet unless brass was carefully selected and loaded rounds run through a Redding .32 S&W Long Profile Crimp Die to size the case body so that rounds would chamber.

A proven recipe which works in all .32 ACP pistols is the Accurate 31-081H cast from wheelweights, sized .311" and loaded with 2.2-2.5 grains of Bullseye at 0.955" minimum overall cartridge length. Hard alloy is unnecessary. The 2.5 grain load should be considered maximum, but is safe in the wartime, steel-framed pistols. For the Keltecs, and Beretta Tomcats work up from 2 grains and adjust the charge as needed to produce reliable function, not to exceed 2.2 grains.

268970

The Fouling Shot published a good summary of .32 ACP historical info and load data. If you would like a copy of that magazine PM me with an email address which can accept a 1MB .pdf attachment

[mattw]

I knew Outpost75 would show up here... 32ACP guru indeed.

[CastingFool]

That's awesome! Outpost75, just sent you a pm, with my email address, asking for the pdf file. Thanks!

[Kosh75287]

32 ACP is a pain it the butt to reload, but they will reward you with good results if you do it properly.

The FEW times I reloaded .32 ACP, I used Unique and some 77(?) gr. cast bullets (NOT wadcutters), and the "P.I.T.A." aspect of reloading it made itself known in no uncertain terms.
Normally, I really LOVE Unique, in nearly any pistol/revolver cartridge, but its so-so metering qualities made it a chore to use. It didn't take long for me to develop an appreciation for ball powders in certain applications.
The .380 ACP, which I reload in far greater quantities, is nearly as much of a chore, unless I use a propellant like W231 or AA#5. I'm not a huge fan of W231 (it's a perfectly fine powder, I just prefer others), but I keep a pound of it around, exclusively for reloading pocket-pistol rounds.

[mr surveyor]

It seems like I remember that "Rimlock" could be a major issue with the semi-rimmed .32 acp. I still have a KelTec P32 I bought for my wife about 15 years ago, but it's the only centerfire I have that I never reloaded for. I do remember the warnings about using the shorter oal jacketed hollow points, and the potential for rim lock ...


jd

[Outpost75]

That's awesome! Outpost75, just sent you a pm, with my email address, asking for the pdf file. Thanks!

On the way to you.

[Hanzy4200]

I currently cast for 6 different .32's. I size all to .311 out of logistic sanity. All but one shoot these very accurately. I just dont have the time or inclination to slug all 6 barrels and size differantly for 2 pistols.

[mattw]

Rimlock can be an issue, but it is an OAL issue and fairly easy to address if you roll your own. They are a PITA to load! I actually use titegroup and 2400 in most of my loads. W231 is passable but tough to meter in the 1.9 to 2.1 grain loads. Has been tough with all of my measures, the Lee PPM does it best. Bullseye has been good for me as well, meters better also.

The only larger PITA is 25ACP and I have quit loading it as I could not stand loading it... I sold the gun! :) Still have a few hundred brass and about 150 commercial loaded rounds just in case.

[CastingFool]

Thank you, Outpost75. Received the pdf file, and will be printing it soon.