Does anybody know what, if any, weapons were chambered for this round?

Does anybody know of a source for Evaluation of 6.35MM Simplex and Duplex Ammunition, reportedly published in 1960 by the Infantry Board?

The web says you may buy it from ntis.gov/


Your easiest source for the basic trials info on the 6.35mm and 25 Winchester cartridges is the book SPIW:The Deadliest Weapon That Never Was by Stevens & Ezell. You can still find copies for sale on the various web sites that sell books.

Our own Daniel Watters also wrote articles for Gun Zone which you should be able to Google.

I’ve never had much luck getting anything from NTIS. If you do, would you let me know.

I did a description of the various cartridges on the old Forum. Maybe it’s still there but the photos are probably gone. I have the photos in my files if you’d like to see them. Let me know.

One last nit pick detail. The cartridges are the 6.35mm Ball FAT116E1, FAT127, and FAT124, and the 25 Winchester FAT115 and FAT 116. There is no case length in the official designation.


Thanks, Vlad – tried doing a search there, but got no results.

Thanks, Ray. I read that book a number of years ago. Must’ve forgotten that it had anything on the subject.

Yes. In fact, earlier this evening I was reading his thegunzone.com/556dw-1.html and that page provided some of the info in my first post in this thread. Unfortunately, he didn’t note which rifles were chambered for the 6.35mm rounds.


Before starting this thread I searched the forum and found three, old 6.35mm threads. In one you posted weight and measurement info of five specimens that you pulled the bullets from. I don’t recall if there were any photos of yours, so sure, if it isn’t inconvenient, I’d like to see them.

Yeah, I saw that “nit pick detail” in one of the old threads, too.



Here are the cartridges used in the Ft Benning Infantry Board Trials in Nov/Dec 1959. I think the same were used at Ft Greely for the Arctic tests. Also included was the Cal 22 Springfield Armory design (224 Springfield) but all references to that cartridge were excised from the reports because it’s inclusion was not authorized.



Here are the cartridges used in the Ft Benning Infantry Board Trials in Nov/Dec 1959. I think the same were used at Ft Greely for the Arctic tests.

Thanks, Ray. Good photo! Now I need to locate a copy of the SPIW book and see if it tells what rifle(s) the 6.35mm rounds were fired in.



I believe that the 7.62mm was fired in an M14 and the 22 Arrow in a highly modified Winchester M70. I’m not sure about the 6.35MM but since this was part of SCHV and the 6.35MM was supposed to be an alternative to the 5.56MM, maybe they were fired in modified ARs?? I have the book but don’t recall seeing the rifles mentioned, and I don’t have time to look. Maybe Daniel is reading this and can tell us?



OK, curiosity got the best of me so I took a quick look at SPIW to see what it said about the 6.35MM rifles. Here is all that I could find:

Weapons provided to fire the 5.6mm and 6.35mm cartridges were modified commercial sporting rifles and were not evaluated as hardware items.

So, if I had to guess, I’d say they were probably Winchester M70 or Reminton M700 rifles. The Winchester 22 Arrow rifle is shown.


Thanks again, Ray. It would’ve certainly been feasible to convert an AR-15 to fire the short (1.880" case) 6.35mm rounds, since they have the same length as 5.56mm, but apparently the project never advanced to that stage.



You’re correct that the AR could have been modified to fire the short 6.35mm cartridge. But the Ft Benning trials were to test only the cartridges and so single loading was OK. And you’re right again, it never got past that stage. In fact, it should not have gotten to the Ft Benning trials to begin with. The 6.35MM cartridges were a diversion intended to de-rail the AR15 and the 5.56 mm. People like Stoner and General LeMay didn’t let that happen and the rest is history.


Here’s the book

I’ve never seen any reference to the specific rifles used as testbeds for the 6.35mm experimental cartridges.

I’d almost bet the mansion that they were plain old Winchesters or Remingtons that were re-barreled and chambered for the cartridges. They’re probably lost to history.


Thanks to another Forum member we can pin down the firearm used to develop the 25 Winchester cartridge.

Apparantly, in 1970 or 1971 a collector asked Winchester to provide provenance for a Model 70 rifle in his possession. Winchester responded with a letter confirming that the rifle was one of two used by Winchester to develop a cartridge under Army contract, then called the 256 Winchester. The rifle was made especially to fire the experimental cartridge and must have had a short barrel, possibly a Featherweight contour, although the letter does not say so specifically. The letter does say ,“the short barrel was a requirement since it was believed, correctly, that Military Arms of future times would have this feature.” It also says that the other rifle was used extensively for testing and was “destroyed in the process.”

So, it appears that the cartridge was originally called the 256 Winchester, was later changed to 25 Winchester, and is now known by it’s military designations FAT115, FAT116, and FAT116E1.

It doesn’t answer the question of what rifle was used in the Ft Benning and Ft Greely trials in 1969 but it certainly lends some weight to the possibility that they were Winchester Model 70s.


Considering all of the info in your post, I’d say it was a virtual certainty that Model 70 Winchesters were used.

I do wish the barrel length had been stated. I’d guess that it was 20 inches, considering that was the AR15 barrel length and Winchester’s short 6.35mm round was given an OAL that would’ve enabled it to be used in a converted AR15.

I just found out that at least one T44E4 rifle was converted to fire 6.35mm. Probably the long (2.080" case) version?

museum.nps.gov/spar/vfpcgi.e … RDS=6.35mm

Or possibly the Cal 25 for Light Rifle. Note the 1955 date. Is there any way to contact someone who might be able to provide more information?


Also located at the SPAR site are several modified Remington Model 722 bolt-action rifles with .257 barrels.

Some have barrels marked "SHORT CART"
museum.nps.gov/spar/vfpcgi.e … WORDS=.257

Others have barrels marked "LONG CART"
museum.nps.gov/spar/vfpcgi.e … WORDS=.257

That’s possible. I just figured that a “modified” bolt would only have been necessary for use with the smaller-diameter 6.35mm case.

Shouldn’t a standard bolt have been good for the .25 cal Light Rifle cartridge? It did use a necked-down .30 case, right?

1955 may be the date of manufacture, but not necessarily the date of conversion?

I sure don’t know. But, on a related note, I was talking to Frank Hackley this morning. He said that among the items listed in inventory at Frankford Arsenal when it closed down were about half a dozen 6.35mm M16s.