Designed in 2002, the Heckler & Koch XM8 was a lightweight assault rifle that aimed to replace the original M4 carbine in U.S. Army service. Based on Germany’s G36 rifle, the XM8’s futuristic appearance and extensive use of polymer made it popular in video games of the time. But the Army canceled the program and opted to stick with an improved M4A1 carbine.
Now, the XM8 is back on the military’s books, as the carbine version of the M7, courtesy of SIG Sauer.
Also Read: The infantry hates the XM7 rifle (and why the Army doesn’t care)
Following its experimental adoption under the Next Generation Squad Weapon program, the SIG Sauer XM5 rifle was redesignated the XM7 to prevent confusion with the commercial Colt M5 carbine.
Officially adopted as the M7, the new SIG rifle has faced criticism from soldiers, especially for its weight.
Equipped with a suppressor and electronic fire control system, an unloaded M7 weighs over 13 pounds. For comparison, the M14, which was quickly replaced by the M16, weighed just over 9 pounds unloaded. At SHOT Show 2026, SIG Sauer displayed a carbine version of the M7.
Unnamed at the time, the shorter, lighter M7 has received a National Stock Number (NSN 1005-01-737-3402) under the designation XM8. This makes the new carbine easy for testing units to procure.
In addition to a tapered and shorter barrel, down from the M7’s 13.1 inches to 10.9 inches, the XM8 ditches the folding and telescoping stock for a fixed, telescoping stock like that of the M4. Unloaded and without accessories, the XM8 weighs 7.3 pounds. The carbine’s suppressor also shaves 1 inch and 0.15 pounds off of the M7’s can.
With a shorter barrel but the same 6.8x51mm ammunition, the XM8 will have a decreased bullet velocity compared to the M7. However, the modularity of the MCX-SPEAR system on which the NGSW is based allows for relatively quick barrel and handguard changes at the unit armorer level. Interestingly, accuracy is reportedly better with the shorter XM8.
Developed under the M7 Product Improvement Effort, the XM8 aims to address issues experienced by soldiers with the M7. SIG Sauer reports that barrel life is the same as that of the longer M7. Troop evaluations will reveal if Capt. Braden Trent’s observations of unusually high barrel wear in the M7 persist in the XM8.
At SHOT, SIG Sauer told TFB TV that the carbine version of the M7 would be available to the civilian market. However, calibers, pricing, and release date were not specified. So, not the XM8 some may have wanted (still waiting, H&K), but hopefully the XM8 that troops need.
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