In the first part of this story, we looked at the least technically advanced of the 1979 contenders in the final round of US Army Squad Automatic Weapon tests: the XM106 Automatic rifle, a heavy-barrel M16A1 with a bipod, quick-change barrel, and ability to fire from the open bolt. In the second installment, we started telling the story of the most technically advanced contender, the XM248, but to do that we had to look at the history of the competition and its forerunner, the XM235.
As we left the competition, in approximately 1977, the XM235 certainly had the inside track. The Army reluctantly abandoned the idea of a 6.0 x 45 mm cartridge, and chose to stick with the 5.56 for logistical and Alliance-political reasons.
One of the things that the innovative team at Rodman Labs did, before giving up the XM235 project, was to build a version of the gun for the 5.56 cartridge. (It’s not clear whether the 5.56 mm gun was made before, after, or at the same time as the 6.0 x 45 mm XM235). In everything except those detail changes forced by the caliber switch, the 5.56 XM235 was identical to the 6.0 mm gun: it had the two-tube receiver; the dual gas pistons; the rotating cam to drive the belt feed; the centerline, center-of-gravity mount for the ammunition-belt can; and a pistol grip offset to the right to clear the can, but directly on the weapon’s longitudinal CG.
Ford Aerospace, which beat out Maremont for the XM 248 contract, was expected to do certain things to develop the weapon. The Army wanted it made ready for production, and produced in a short pilot run of 18 guns and accessories. They wanted all dimensions and measures to use the international metric system — Rodman had been working with inches and pounds, and in the mid-1970s, the Ford and then Carter administrations had committed the USA to metrication — something that would be dialed back to “voluntary” in the Reagan era (one of the few lasting effects of the government’s 1975-82 push for SI weights & measures was their use by the military for most measurements, which would continue). And the Army customers were willing to trade off some of the XM235’s remarkable controllability for a weapon that was suitable for ambidextrous operation: as a bullpup design, the XM235 favored the right shoulder, and the right-offset pistol grip compounded that.
Ford wound up making two distinct versions of the XM248, the first meeting the Army’s minimum requirements and incorporating a few Ford “Better Ideas” (to use one of the car company’s 1970s marketing slogans), and the second incorporating a wider range of improvements.
The first XM248 had the pistol grip moved back (from period images, about five or six inches) behind the feed mechanism and the “belt box” that was meant to hold link belts. The belt in a box was improved to offer “two-step load & go” capability; unlike other light machineguns, the a/gunner or gunner of the XM248 never needed to touch a belt. It was fully metricated, naturally. Further human engineering improvements included an ambidextrous charging handle under the forearm, an insulated forearm grip (the XM235 had only a sheet metal handguard, which tended to get uncomfortably warm in operation) and a larger (longer) buttstock. Ford touted the extended stock as a place to stow a spare bolt, but it was really extended to put the gunner’s trigger hand and firing shoulder back in the proper relationship, after moving the pistol grip!
The resulting gun was only a couple inches (or, in proper SI units, 5 cm) longer than the M16A1 (41.7″/1060mm), but it delivered 100 to 200 of the developmental XM777 rounds before reloading. It had a cyclic rate of 500 rounds per minute (on the slow, and therefore controllable, side) and weighed 11.7 lb. (5.3 kg) empty.
It also had the longest barrel (24″/609mm) of the contenders.
The changes in the second version of the XM248, which is the version produced in a quantity of 18 for development and operational testing, were many but generally subtle. The safety was redesigned to be more positive; the 100- and 200-round “Load and Go Ammunition Containers” were completely redesigned, the forearm and buttstock were also redesigned (the latter losing its bolt storage, and shortened by 0.3″/8mm). The sights, bipod, and disassembly of the bolt were all tweaked, and many changes were made with a view to production — after all, the XM248 had the inside track in the competition. Internally, these guns were functionally the same as the brilliant, world-beating XM235.
The most significant changes were probably some external ones — to better adapt the weapon to standard Army accessories, like the M122 tripod and an unspecified night vision weapons sight (probably the AN/PVS-2).
This was the American contender, meant to go head to head with the Belgian and German guns — for H&K had gotten back into the competition after their disaster in DT/OT1. And their contender, the XM262, will be the subject of the next installment. We’ll finish with the evolution of the FN Minim/XM249, and then discuss how the actual competition shook out.
Thanks for joining us on this trip back to the 1970s!
(Note: most of this information comes from Smith & Ezell, Small Arms of the World, 11th Edition  and 12th . Some came from DTIC docs and period trade magazines like Armies & Weapons. Having several editions of Smith & Ezell’s work is extremely helpful to the researcher; unfortunately it is no longer kept up to date, and the “yearbook” add-on, Small Arms Today, died with Dr. Ezell).