TC 3-22.12 governs operation, maintenance, marksmanship training, and combat techniques for the M26 Modular Accessory Shotgun System.
View TC 3-22.12 on armypubs.army.mil
TC 3-22.12 covers system configurations, ammunition, clearing, assembly, cleaning, firing, malfunctions, and destruction. It also requires training in marksmanship, nonlethal engagements, ballistic door breaching, and range safety.
The MASS can hold six rounds: five rounds in the magazine and one round in the chamber. (paragraph 2-13)
For safety reasons, keeping a round in the chamber is not recommended. (paragraph 2-13)
During training, eye protection is required to protect the firer from projectile bounce-back. (paragraph 2-13)
System operators must be trained in M26 MASS disassembly and assembly before placing the MASS in the stand-alone configuration. (paragraph 3-1)
The aimpoint for all lethal antipersonnel ammunition is the target's center of mass. (paragraph 4-27)