The Barrett M468 was a variant of the M4 Carbine, rechambered for a heavier and larger 6.8mm bullet for increased terminal performance.

It was an attempt to create an optimal Special Operations close-to-medium range carbine for Close Quarter Battle (CQB).

The larger 30-round Barrett steel magazines were an inch longer and weighed 5 ounces more (0.569 lbs.

[8][9] Precision Reflex Inc. (PRI) made a 25-round steel magazine that was 7.2 inches [183 mm] long and weighed 8.4 ounces (0.525 lbs.

The civilian-market version of the M468 shipped with a soft carrying case, cleaning kit, sight wrench, and two 25-round PRI magazines.

[6] The weakness of such a system is that it distributes hot gases and unburnt propellant directly into the rifle’s receiver, leading to overheating and potential stoppages if regular maintenance and cleaning protocols are overlooked.

[11] The M468 has been largely replaced by its upgraded version, the Barrett REC7, which operates via a short stroke piston that minimizes the direct impingement rifle's issues with gases in the receiver.