.32 ACP Vs. 7.65 Browning Case Spec Variation

#1

Hello,

After a lot of head scratching, some years ago now, I figured out that some manufactures produce 7.65 Browning cases with significantly different extractor groove geometry than others, and that this has a strong effect on reliability of many pistols chambered for this cartridge.

I first encountered this when a friend’s Nazi proofed Walther PPK demonstrated an intolerance for every US load except Winchester’s, and any/all european-manufactured loads.

Later, I found the same bias in other european pistols, including the Hungarian PA-63, Spanish “Ruby,” and FN/Browning’s FN 1900.

What happens, to the best of my ability to determine, is that most US manufactured .32 ACP cases fail to fully nest their semi-rimmed “over-diameter” fraction of their rims within the extractor groove of the underlying case. As a consequence, a tiny gap is formed between the web areas of the straight walled bodies. This gap creates an additive error, which after a certain number of cartridges, will create a failure to adequately support the top cartridge in the magazine while it is being fed, causing feed jams.

There are a couple of solutions I’ve found. One is to short-load the magazine to fire only the number of rounds of a particular US-type the weapon can reliably cycle. The better solution is to use cartridges with the larger-pattern extractor grooves.

My questions to you gentlemen are:

Do we have two standards here? Is there in fact a US standard case and a european standard case?

Did Winchester always make their cases like the european cases, or are they in fact simply now using european manufactured cases?

What US manufacturers, particularly prior to 1990, made .32 ACP cases with these larger extractor grooves?

Are there guns which actually work better with the scant extractor grooves seen commonly on US-made cases?

Thank-you for your assistance. I’ve got a thorny forensics question that this pertains to.

Regards,

Charlie

#2

Yes there are standards. SAAMI (here) & CIP (across the pond) are in play with ammunition manufacturers at the moment. In the past I don’t think there were such strict and detailed standards so makers had more tolerances in setting-up the machinery to cut extraction grooves, under-rim cuts, & rim profiles and all the other things that make a round function. The same on the other end for the weapons themselves from maker to maker.

Perhaps I’m not really answering your question?

As to Winchester production (or almost any brand name) a current rule of thumb is everyone makes everyone else’s cases. CCI / Speer had/has a code of dots & dashes for other makers brass made with their name on it. So Winchester, Remington, Federal & other companies made brass that said CCI or SPEER on the headstamp. If you knew the code you could say oh Winchester made that. Actually I think I’ve heard of Chinese made cases with the Winchester headstamp. & how about the current blue Colt boxes made in Russia or Mexico.

Major ball of worms here.

As to firearms function & suitability;

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#3

Pete,

Thanks. That both clears things up enough to answer my basic question and muddies it back up enough provide an excellent excuse for not chasing this farther. Much obliged,

Charlie

#4

Charlie, I’ve had the same problem with a government marked .45 pistol and new, factory ammunition. The extractor wedged on the forward slope of the extractor cut and prevented smooth chambering. However, the pistol worked fine with other lots of ammunition including reloads with SWC shaped bullets.

That sounds much like the problem you describe. From this I deduce that while SAAMI has strict standards for pressure, velocity and chamber dimensions, the extractor cuts are a bit looser in definition. Also I note the case wall thickness can vary from lot to lot, resulting in very nice fitting bullets to quite loose bullet seating. (But that’s a different discussion.)

I have a collection - about a dozen so far - of older (what I call ‘art deco’) pistols chambered for .32 ACP/7.65mm. I have some European and some U. S. made pistols. (No Spanish guns yet; I’m looking for a proper Ruby.) All the pistols in my collection function well in all regards with Prvi Partizan ammunition.

Also, I’ve picked up a few odd rounds from the era (1900-1930 or so); Kynoch, Eley, Remington-Peters. I will take some photos of the extractor grooves. If all goes well I will post them here and perhaps we can observe something.

I’ve also read your other question about bullet construction. I’ll see if I can help.

EDIT: I still can’t post a picture. I have pictures of headstamps and the extractor groove profiles for several .32 ACP/7.65mm cases of various manufacturers.