While initial media briefs on the systems set to replace the M4 Carbine and M249 SAW on the Army’s frontlines held back some details, the specs are now public.
The largest and most sweeping small arms program developed by the U.S. military since the 1950s, the Next Generation Squad Weapon initiative recently picked Sig Sauer to provide the XM5 rifle and XM250 light machine gun to replace the M4 and M249, respectively. Both weapons use Sig’s in-house developed SLX suppressor system and 6.8x51mm cartridge– sold on the consumer market as the .277 Sig Fury. Meanwhile, the platforms will use an integrated optics system developed for the purpose by Vortex.
A briefing by the Army last month immediately after the announcement that Sig was the tentative winner to supply the XM5 and XM250 was fuzzy when it came to weights and dimensions.
“So, I — so the weights are — I’ll give a comparison to the M4 and the 249 in general weight difference,” said Col. Scott Madore, PM Soldier Lethality when asked. “So, the rifle — the Next-Gen Squad Weapon rifle is about two pounds over the M4. Now the automatic rifle is actually four pounds less than the current M249 squad automatic weapon.”
Now the Army has released the figures, with the XM5 listed as 8.38 pounds, and 9.84 with its suppressor attached. The overall length, with the suppressor attached, is 36 inches with the side-folding stock extended and the standard 15.3-inch barrel. By comparison, the service lists the weight of the M4A1, complete with backup iron sight, sling, adapter rail system, and an empty magazine, as 7.74 pounds. The length of the M4A1 with its stock extended and without a suppressor is 33.82 inches.
Like the combat load of the XM5 compared to the M4, the XM250 user will carry fewer rounds at a heavier weight, described as four 100-round pouches, at 27.1 pounds. The M249 light machine gun combat load, which is three 200-round pouches, weighs 20.8 pounds.
Is the juice worth the squeeze? The Army thinks so, saying the benchmark for the 6.8 cartridge was that it weigh less per round than the 7.62 NATO.
With that in mind, in a very real sense, comparing the XM5/XM250 to the M4/M249 is an apple to oranges situation, and it may be more appropriate to journey back to about 1965 and compare the new guns to the M14 battle rifle and M60 machine gun, both of which were in 7.62.
The basic wood-stocked M14 hit the scales at 9 pounds empty and was, initially, carried with five 20-round magazines, later increased to seven mags. A 140-round combat load of 7.62 carried in seven steel M14 mags is 11.2 pounds, or about 1.5 pounds less than the same quantity of 6.8 as carried with the XM5.
The M60, which was often derided as “The Pig” due to its weight, took cues from the German MG42 machine gun and, even with the use of early plastics in its furniture, weighed 23 pounds when introduced, although this was later whittled down to a more carry-friendly 18.5 pounds, both figures significantly heavier than the XM250.
As noted by the Army, “The 6.8 mm has proven to outperform most modern 5.56mm and 7.62mm ammunition against a full array of targets.”