.32 ACP vs. 7.65mm Browning

I have always assumed the .32 ACP and the 7.65 Browning were the same cartridge. The page below is from the 1911-12 Remington-UMC catalog and show them as two seperate loadings. Anyone have any idea why? Note that the only difference in the illustrated headstamps is the .32 says “.32 ACP” while the 7.65 says “.32 AP”.

Notes I made from the U.M.C. Log do not indicate any particular difference between the two headstamps, and in fact, never actually mention the more prevelent of the two, the “.32 A.C.P”. headstamp. The log showed many changes to the two cartridges, which are entered separately, but for the most part, the changes mirror each other in the two sets of entries.

Weighing and measuring my specimens with both headstamps showed no appreciable differences:

U.M.C. .32 A.P.

Rim: .353"
Base: .335"
Neck: .335"
Cartridge Weight: 118.7 grains

U.M.C. .32 A.C.P.\

Rim: .355"
Base: .335"
Neck: .336" (Yes, .336" not a typo)
Cartridge Weight: 117.2

My two cartridges with A.P. Headstamp did have slightly heavier overall weight than two rounds with A.C.P. headstamp and the same features. The measurements shown above were pretty consistent with both of the A.P.-headstamped loads I have, and my five or six variations with U.M.C. .32 A.C.P. headstamp also fell in with measurements very close to those shown.

I am not willing to ascribe a heavier powder charge to the A.P.-headstamped rounds based on such a tiny difference in overall cartride weight. It may be simply coincidental that in both cases the A.P.-headstamped rounds were slightly heavier. My notes from the Log show that while changes were made more than once in the powder charge of these cartridges, they remained the same in both of them.

The fact of two different catalog entries and two different headstamps may be nothing more than a gesture to the European gun makers to have ammunition exported for use in many different brands of firearm not headstampmped specifically for the Automatic Colt Pistol (A.C.P.). I don’t know that - I simply can’t see any other reason for it. It does mention that boxes for the “A.P.” rounds would be marked in the metric 7.65 mn/m designation. As we know, later on, Remington, for a time, headstamped their export .32 auto rouns as “REM-UMC 7.65m/m.”

Regarding possible differences in rim thickness, bevel, etc., the log made clear that attemps were made to have all of the cartridges of either headstamp work in the Colt and FN pistols alike. It is interesting that they even bothered to keep two separate entries, especially when initially, both the “.32 Browning” and the".32 Colt Auto" entries indicate the headstamp was to be “.32 A.P.”

It is too bad that the early catalogs do not often show muzzle velocities for the various cartridges contained therein.

also the Fiocchi catalog of 1926 lists the same cartridge with 2 names:
number 72: 7,65 mm per pistole Browning mauser beretta
number 73: 32 Auto Colt

However in the fiocchi catalog they differ for their bullet weight:

7,65 browning: 4,80 grams
32 Auto colt: 4,90 grams

Pivi - like any caliber that has been manufactured for years (in the case of the 7.65mm Browning/.32 A…P. for well over 100 years now) and by almost every ammunition manufacturer of any note in the world during that span, you will find variations in all things, especially bullet weight. I have a good collection, but not a fabulous one of this caliber, and it has over 1,000 specimens and I don’t collect different dates. However, it doesn’t bear on the question of those made by U.M.C. simultaneously, showing the same specifications, but treating them like two different cartridges.

Regardless, thanks for the information on the two different bullet weights in Fiocchi. I had not noted that before. I’ll have to weigh some of my Fiocchi rounds to see what I can see.

Yes,I agree.I wote my post because I have found the same cartridge with the double name as in the UMC catalog.In that catalog the bullet weight is the same for both of them but in the Fiocchi one is different

Prior to WW1 Eley Brothers listed the ‘.30 Browning’ and the ‘7.65mm A.P.’ seperately - and they are mounted and labeled seperately on Eley cartridge boards.
I have Eley drawings which show slight dimensional differences in bullet diameters between US & European types. See also the book ‘Webley Automatic Pistols’ which discusses this issue. Sorry can’t supply any more info at present - still in UK on way home from SLICS - back home next week.

[quote=“JP-C”]Prior to WW1 Eley Brothers listed the ‘.30 Browning’ and the ‘7.65mm A.P.’ seperately - and they are mounted and labeled seperately on Eley cartridge boards.
I have Eley drawings which show slight dimensional differences in bullet diameters between US & European types. See also the book ‘Webley Automatic Pistols’ which discusses this issue. Sorry can’t supply any more info at present - still in UK on way home from SLICS - back home next week.[/quote]


I said that before on another post but people didn’t take any attention.(it was in the topic on subsonic 7.65 Brg)
We have a difference in bullet diameter depending of the manufacturer (sompe are at the us standard, some are at the european standard)

JP–What are the two bullet diameters, in both metric and inch?

With any cartridge made for over 100 years by some 50 or more different factories, for use in hundreds of different guns, there will be variations in dimensions, especially since the cartridge and the guns made for it predate CIP or SAAMI by many, many years. While it is interesting to note that some European dimensions varied from the more or less standard American dimension, it doesn’t completely speak to why U.M.C. showed the two different entries in their catalog, especially since their production log shows many, many changes in both cartridges, often the identical changes, from its first production of the “.32 Cal. Browning” in December 1899 and of the “.32 Auto Colt MC & SP” in February 1903.

Winchester production goes back until at least February 1898, and probably before that, as the label for NPE cases from that date refer to “The .32 S&W Rimless” and a change in the case length, intimating that those cases were NOT the very first step in the design of what became the .32 A.C.P./7.65mm Browning cartridge.

All that is clear is that the early U.S. production of the round was intended for John Browning and his associates, and that it was only later that Colt came into the picture, as Browning sold production rights to them and others.
I am not at all sure from anything I have read anywhere why it seems to have initially evolved towards two different cartridges due to bullet diameters, unless it was simply something to do with the change from Browning’s inch measurements to those of the Metric System when FN entered the picture on this cartridge. It is not at all clear in UMC’s records
why they maintained two desginations for this round. In fact, the opening entry in April 1903 for the Colt version begins with the statement “These cartridges are the same as Browning.” That statement begs the question as to why they continued to make entries under the original “.32 Cal. Browning” designation until March 1907, the date of the last entry. Entries for the Colt version went on until August 1912, about as late as any entry in the entire log, as the log was discontinued not long after Remington really assumed operating control of U.M.C. (or vice versa).

Regarding bullet weight, while there were many changes to the case, bullet and powder (as well as powder charges), the only entry for either designation regarding change of the bullet diameter is not under the .32 Browning, where one might expect it if the changes was made to meet a European ideal, but under the .32 Colt designation. That last entry of August 1912 indicates “changed size of bullet to .311 - .312”.

Unfortunately, the original size of the bullets initially manufactured by U.M.C. is not shown within the entries for either deignation, Browning or Colt. However, a soft-point bullet we pulled from its U.M.C. case measured .307" (7.80mm) while that pulled from an early copper “U” primed REM-UMC case, also a soft-point bullet but of quite different design than that from the U.M.C. case, measured .3115 (about 7.9 mm).

All of this is interesting, and fooling about with this question has taught me some things I didn’t know about this little cartridge, especially regarding U.M.C. production, but in my eyes, there is still no clear picture of why U.M.C. in their 1912 catalog showed the round under two diffent names. I do not think that the answer is in the bullet diameter, not only because of the U.M.c. entries, but because with a published spread of measurements from .303" to .313" (EB69) for various manufacturers about the world, it is hard to draw conclusions based on variations of bullet diameter alone. Further, neither designation, .32 A.C.P. nor .32 A.P. (.32 Browning A.P.) were generally used in Europe at all, where the cartridge was normally called 7.65mm Browning, or variations thereof. Even U.M.C. alluded to changing the designation for export to 7.65mm, and some early Remington-UMC rounds for export were headstamped 7.65mm, rather than .32 A.C.P. or .32 A.P.

Different calibre designations could differentiate between different pistols. Early Webley auto’s were marked either for metric or imperial calibre designation - until just prior to WW1 when the two dimensions were rationalized into one calibre - between .308 & .311 inches and Webley slide markings indicated use for .32 ACP & 7.65mm ctgs.

Hi John - nice meeting you at SLICS. Wish the show wasn’t so busy - all you ever have time to do is say hello to friends, there are so many there.

Regarding your comment, you would think if that were the case in the instance under discussion, that the U.M.C. catalog would have stated what pistols were deemed proper for each caliber.

I suspect we will never have an absolutely positive knowledge of what they felt was accomplished with the two listings.

As late as 1917 Remington-UMC was still listing both rounds. The nomenclature had changed a little to "7.65mm Browning (32 Cal.)"and “.32 Automatic Colt Pistol”. In 1923 the two are combined into “.32 (7.65 M/M) Automatic Pistol”. So, for whatever reason, they were listed as two different cartridges from 1911 to at least 1917.

John Moss–If you go back and look at the 1911/12 page I posted, they do indicate what pistols they were adopted to. But, the list is essentally the same for both rounds.

Ron - I did miss that about what guns they were for. Couldn’t read the small print too easily. I note that the two lists are NOT identical. the second cartridge does not include Savage Auto Pistols. That is interesting. I wonder if it was due to some difference in the cartridges that caused poor function of the “Browning AP” version, or if it was due to some other reason.

At any rate, as you said, they duplicate each other somewhat and don’t actually name many pistols and it doesn’t answer the “export” angle at all, since both cartridges are shown for the foreign pistols on the list; it is only the domestic Savage autos that seem to be left off of one list.

Also interesting is the information about the years the double entry remained on the Remington-UMC lists. I wish I had these early catalogs. Big hole in my library. Too many of them to seek out at my age. Despite a life-time of study of auto pistol cartridges and the pistols themselves, I still can’t grasp the reason for it based on the information we have. I have measured my cartridges marked AP against those marked ACP and find no appreciable differences that can’t be traced to entries in the log about changes which, in most cases, were to cartridges carrying both designations. They all seem to fall into reasonable tolerances, ie: The same cartridge. The only highly technical cartridge specs I have for Remington, as opposed to U.M.C., are from much later.

I will have to look thru my Winchester catalogs of the same WWI era and see if they show two different rounds. If there really was a concrete reason for two separate cartridges, I would think Winchester would have made them as well.

There is something I can’t understand:
if the 7,65 mm browning and the 32 ACP are listed as different calibers (as JP oand others noted there are some little differences in bullet diam etc) I don’t understand why in the fiocchi catalog the 7,65 mm Roth steyr and the 7,65 frommer are described as the same cartridge

Pivi - I think you mean the 7.65 Roth-Sauer, not “Roth-Steyr.”

The 7.65 Frommer is higher velocity than the Roth-Sauer. The Frommer version has a muzzle velocity of 340 mps (1115 fps) while the Sauer loading, in exactly the same case and with the same bullet is loaded to 326 mps (1069 fps( (EB71 & EB77).

It is the same basic circumstance as with the 9mm Glisenti and 9mm Parabellum, both having the same case and bullet (of course the bullets in 9mm Parabellum vary wildly in shape and weight over the years, as do the velocities within similar 7.5 and 8 gram (115 and 124 grain) bullet-weight ranges). I never understood why it was necessary to give the “Glisenti” a different name, since in 9mm Parabellum, with 115 grain bullets, for example, velocities on factory loaded, ordinary ball cartridges can range from about 1050 fps to at least as high as 1295 fps.

Regardless of what I think, the fact is, they have been given different names and at this state, for the most part, not to use them is more confusing than the original idea of giving virtually identical cartridges different names just because of velocity and pressure.


I find the dual listing of 32 ACP and 7.65mm Browning very interesting! Although I don’t really collect this caliber, I do have a very minor collection of Browning M1899 (short side plate) and M1900 pistols (to go with many many Chinese copies of the M1900).

My personal opinion, based on the early history of the M1899/1900 pistol is that the 7.65mm Browning cartridge was probably developed in Belgium by FN as they evolved the Original Browning prototype pistol they obtained in early 1897 into the M1899 & M1900. The FN developed cartridge was undoubtedly based on ammunition Browning supplied with the prototype pistol. I think Colt also had an interest in a .32 pistol (eventually the M1903) and the original Browning design ammo ( probably made by Winchester) continued to evolve in the US to support the Colt effort. The result was two seperate designs that turned out to be interchangable. I think the fact that they were two different designs is why they show up seperately in the Rem Umc catalog that Ron illustrated for us. Note, though the bullet weights are both shown as 71grs, the drawings show two distinctly different ogives. Jean-Pierre in an earlier thread said that US bullets and European cases are not necessarly compatable for reloading the 7.65mm Browning. I wonder if the US cartridge specs and the European cartridge specs are the same!!!

The following are the facts as I know them from the various references available, along with some great info from John Moss. I have also included my assumptions at each point. These assumptions seem to me to be a logical part of the evolution of the Browning pistol.

I’d be interested in seeing a check list of headstamps for the 32 AP/ACP/7.65mm Browning cartridge. Anyone got one handy?

Lew’s synopsis is very interesting and having discussed this with him in length over a period of time, I find that I agree with most of what he has written.

My point of departure is the statement that FN developed the cartridge. To quote Lew’s entry “The FN-developed cartridge was undoubtedly based on ammunition Browning supplied with the prototype pistol.” If their cartridge was based on cartridges supplied by Browning, then it follows that while they may have refined the cartridge in ways to their liking, for proper function in their pistol, they did not develop the initial cartridge. By Lew’s own quote, the basic concept, including in the form of test ammunition, went with Browning or representatives of his or of FN along with his prototype pistol, to FN. Knowing fairly well the history of John Browning and his development of guns and the cartridges for them, I believe it it very safe to say that John Browning developed the cartridge, although it was to be refined by various ways and means at Winchester, FN and later, at UMC. Details such as the best possible powders, whether or not the bullets should have a crimping groove, bullet diameter, soft-point bullet design, etc., were still being attended to by U.M.C. as late as August 1912. I have no doubt that it was a long-continuing process at Winchester and FN as well, although I have not the quantity and quality of information on their productions as that of U.M.C.

The packaging from Winchester that Lew alludes to, which I mentioned somewhere on this thread, records the rounds enclosed as “new length.” This almost certainly indicates that these were not the first of these rounds Winchester produced. If there was a “new length,” then it is only logical that the “new length” replaced an “old length.” Considering Browning’s connections with Winchester, having designed about every gun in their line after the Centennial Model 1876 Winchester (1886, 1887, 1892, etc.), although it is clear their association was “rocky” to say the least, it is my opinion that the round was designed by John Browning at Ogden, Utah, and first made by Winchester. He had to have obtained the ammunition to which Lew alludes somewhere, and there is little reason from a study of all of Browning’s developments to believe that he would have turned out, on machinery used in his gunsmithing shop to fix firearms for the public, and to make his various prototypes, any quantity of ammunition for the prototype pistol. Of course, he could have made up a very small quantity, but even that has no documentation that I am aware of. It is much more likely that while developing the gun/cartridge combination, he had Winchester make up the test rounds to his specifications. It is likely that some were made up and that they are the one that went with him to Belgium, and later modifications were made both by Winchester and by F.N. U.M.C. was a late-comer in the development of the cartridge, but regardless, some development continued at U.M.C. as well, as documented in their log.

Lew asks if “Winchester was doing work in late 1897 and early 1898 in support of FN, or did Colt have an active program to bring out a .32 pistol and perhaps Winchester was evolving Browning’s .32 cartridge for Colt?” While I don’t have a positive, documented answer, I believe it is most likely that Winchester, as early as 1897, was evolving Browning’s .32 cartridge for John Browning. There is no necessity that they would have only been evolving it for FN or Colt. Browning, again, had strong ties with Winchester, and remember that regardless of where Browning eventually first produced his pistol, Winchester was also an ammunition company and had a potential interest in ammunition sales for whatever pistol ended up in the .32 Browning caliber. Browning’s success in gun design already made a bet on his success in marketing, by whatever means (FN, Colt, etc.) a pistol in his then-new caliber, a pretty good gamble. The known package of NPE cases headstamped “W.R.A.Co. .32 S&W”, one of which I have in my collection from the package in question, remains at February 1898, the earliest documented production of the Browning .32 auto cartridge, to my knowledge, and in a sense, again since it mentions a change to an existing design, documents an earlier version. Unfortunately, our best reference on Winchester ammunition, Dan Shuey’s great two-volume set of books, although actually breaking the .32 Auto round down into three different headings, not just two, has no documented information regarding production prior to 1899.

Regarding the direct question Lew asked as Number 7, as to documentation that Winchester assisted Browning in the development of the cartridge, I guess that would depend on whther making rounds for him was the type of assistance in question, or whether redesign hints or out-right design of the cartridge by Winchester is the question. Since we know UMC didn’t get into the act until December 1899, and the earliest documented Winchester ammunition are the NPE cases from the package mentioned, and since that early, the only one KNOWN to be working on this pistol and having produced a prototype was John Browning, I think a fair conclusion can be made, albeit it circumstantial evidence, that Winchester was, indeed, involved with John Browning’s development. All that remains to be proved in my opinion is to what degree that involvment was - design, manufacture, or both.

This is nothing more than my opinion, which I firmly believe is all anyone can offer in the absence of finding positive documented proof of the very beginnings of this cartridge, whether it was at John Browning’s shop in Utah (which for design, I believe to be true), at Winchester (which for quantity production of the cartridge for trial with the prototype pistol, I believe to be true), or at FN The only sure thing is that FN manufactured the very first serially-produced pistols in this caliber, four years before Colt’s Model “M” 1903 pistol.

The Woodin Lab just has just provided three new data points on the early development of the 32ACP-7.65mm Browning.