The Rifle Length Modstock is a dual-purpose stock system which mounts to either a Carbine Collapsible Receiver Extension (MilSpec only) or the Rifle Length Receiver Extension. The stocks are offered in two sizes: M16A1 length and the 5/8-inch longer M16A2 length stock system.
When mounted to the Rifle Length receiver extension the stock will be the fixed at the A1 or A2 length. When mounted to the Carbine Receiver extension the Rifle Modstock can be adjusted for length by using the Carbine Receiver extension’s locking positions and the provided locking pin.
The Rifle Modstock is available in either the A1 length or the longer A2 version. All rifles use the same receiver extension tube; there are no MilSpec or “Commercial” diameters, the only difference is that the A2 rifle uses a 5/8” spacer and longer screw. The A2 length Rifle Modstock kit does not come with the longer screw or A2 spacer.
Note: When mounted to an adjustable receiver extension tube the Rifle Modstock is legally considered an adjustable stock!