25 Homologous Information Needed Please


I have heard of the homologous rounds, but know nothing about them other than the US military was experimenting with them in the 1950s.

I acquired one in a batch of other cartridges a short time ago and need to know general information about their history, why they are called homologous rounds, why were they an improvement over other rounds, and their value if any. Also where would one find a written reference(s) to such a cartridge?

Here is a photo:

The headstamp on the cartridge is WCC 53 with red primer sealant in the annulus. When I found the cartridge it was labeled. The label reads as follows:

.25 caliber Homologous
TEST 3-02307 (although the “7” may be a “1”)
Steel core
WCC 53

Thank you for any information.


The dictionary definition of Homologous helps to explain quite a bit about the name,

  1. Corresponding or similar in position, value, structure, or function.
  2. Similar in structure and evolutionary origin, though not necessarily in function.
  3. Having the same morphology and linear sequence.
    The term comes from the use of the same base case for the vast majority of the rounds used in testing, the .30 FA T1E3, what would eventually become the 7.62mm NATO. This might also be the reason these rounds are called NATO (ie. .25 NATO). The rounds were original designed by Olin Ind. (AKA Winchester) in 1953 and testing continued through 1957 or so. The rounds were made in .18, .22, .25, and .27 cal. There were many variations including tracers, extended case duplex and electrically primed rounds. They all fall under Project SALVO that began in the early 1950

Hi Sht_LE,

Thank you very much. Your information is most appreciated.

I just ordered “Military Rifle & Machine Gun Cartridges”. It should be some interesting reading.


Homologous is a terrible word to use to describe anything. I’m sure the guy who first applied it to the experimental cartridges of the post WWII era had to look it up in the dictionary.

Sht_LE summed it up pretty well. To my simple mind it meant a conventional type bulleted cartridge when compared with the flechettes, duplex bullets, triplex bullets, sabots, etc being experimented with during SALVO, SCHV, SPIW, SSB, and all the other acronymically named programs. (Yes, that’s a real word. I looked it up).

Sht_LE, are you sure the 224E2 was a part of SALVO? Wasn’t it just as much a part of SCHV? Maybe Daniel Watters will read this and set me straight?


The homologous rounds use bullets proportionately identical to the .30 caliber baseline design.



I understand your definition and it makes sense. The bullets for the homologous rounds would be scaled up or scaled down from the .30 caliber bullet design just like maintaining an aspect ratio. Homologous is a terrible way to describe this idea.

Any idea as to specific value??


Good info Teak, I had not known that.

Ray, you are correct, the 224E2 was part of SCHV. So many rounds fall into SALVO I put it in as well. Seems my memory played a trick on me. Maybe next time I will remember to check my referances ;-)

Again I find my self in agreement, Homologous is a lousy name.