7.62mm M198, the cartridge that should not have been

The lesson of Project SALVO was that nothing works quite as well as a conventional rifle, chambered for a conventional cartridge, firing one bullet at a time. But the lesson was not learned so quickly because following the SALVO II trials in December 1957, Operations Research Office (OCO) recommended the development of a standard length duplex cartridge based on the 7.62mm NATO case.

The cartridge showing the most promise was the T314, loaded with two copper-plated steel bullets in tandem. But, a U.S.Army Infantry Board report released in 1959 concluded that the T314 was not suitable for Army use and did not offer a substantial combat advantage over the standard Ball cartridge (7.62mm NATO M59). Unconvinced, the Army continued development of the cartridge through at least two more iterations culminating in the T314E3. In 1964 it was standardized as 7.62MM BALL-DUPLEX M198.

The M198 entered full scale production with the USMC receiving 4 million rounds for additional field testing. But, as the previous Infantry Board trials had concluded, the cartridge proved to be a disappointment. It did not improve single shot hit probability to the extent hoped for, which after all, was the goal of the duplex concept. There have been reports that some units in Viet Nam were equipped with M198 but, for the most part, production was halted and the entire program abandoned in the early 1970s. Reclassified as Obsolete (OBS), no cartridges remain in military stockpiles.

Loose T314 and M198 cartridges can still be found by collectors, but full boxes are becoming very scarce, sometimes fetching more than $100. So, get them while you can.


Excellent review of the 7.62MM BALL-DUPLEX M198 and nice box. Manufactured by FA and WRA, was it ever produced anywhere else say Lake City or by Remington?

Earlier Forum discussions with good information provided by Ray and others:



I wrote that little blurb for another Forum on M14 ammunition. I thought I’d post it here too - new members, etc.


Here is an M4 Bandoleer for the M60 from pilot lot FAPL492 of linked M62 tracer/M198 duplex ammunition. A similar photo has been posted in the past but is no long viewable.


Ray, thanks, if you have pictures of other M198 boxes please post them.

Dave, great bandoleer, thanks. This lot number is mentioned in the report of the service tests with the M60 machine gun conducted by the Army during 1965.



Do you have the report number?


Dave, the number is 375190.

Another box, hope you like. Any way to tell the year?
Anyone else have problems viewing Rays photos? Lately just get X instead of photos.

I see all photos without problem.

I get that blank square with red “X” in the upper corner for some photos on the forum, but all of Ray’s have come through just fine - better than fine, due to the great quality of them - for me too.

Of course, I will never figure out computers. They never do the same thing twice.


The “P” lot number indicates a pre production or pilot lot so they would likely be headstamped no later than 1965.