The rifle must be an M16A2 or M16A4 rifle that was issued by the U.S. Armed Forces or a commercial rifle of the same type and caliber. M16 rifles must be chambered for the 5.56mm cartridge and comply with the following specific requirements:

(1) Modification to make automatic fire impossible without removing, replacing or altering parts is allowed.

(2) Magazines of the standard service 20 or 30 round box magazine dimensions must be attached during the firing of all courses and in all positions. A dummy magazine with a ramp for single shot loading may be used, provided this magazine has the same external configuration and dimensions as the standard service 20 round magazine.

(3) The rear sight aperture may have a hood no longer than 0.70". The rear sight aperture may have a fixed, non-adjustable aperture insert. A corrective lens may be inserted in the rear sight hood.

(4) Rear sight windage and elevation adjustments may be modified to allow finer adjustments. The front sight blade may be fixed or lockable.

(5) To stabilize the rear sight assembly, it may be fitted with one or more pins extending down into the receiver or with stabilizing projections extending forward no more than 5/16" into the top groove of the carrying handle.

(6) The flash suppressor and bayonet lug may be  removed (or the rifle manufactured without a flash suppressor or bayonet lug) to comply with current law. Barrel length must not exceed 20 inches. If the rifle was manufactured without a flash suppressor, the barrel may not be threaded to take one.

(7) A screw may be inserted in the back radius of the pistol grip where it joins the lower receiver. This screw may extend into the rear lock-down lug of the upper receiver for the purpose of securing the upper and lower receivers. The screw head will not protrude above the original surface of the receiver. Both ends of the original takedown pin must remain in place so that the original outside configuration is not changed.

(9) An external device may be attached to prevent selector lever movement to the auto position.

(10) The front sling swivel may be attached to the front ferrule of the handguard or front tip of the "tube" (in the case of a floating barrel system) as long as it remains in the 6 o’clock position and is no more than ½ inch from the original position.

(11) The M16A1 Carbine butt stock or the commercial equivalent may be installed on an M16A2 or M16A4 rifle.