Lage Manufacturing builds custom accessories for submachine guns, and here they make the dreams of millions of geeks come true with a function replica of the Colonial Marine’s M4A1 Pulse Rifle called the MAX-41A:

Submachinegun component is a NFA registered SWD M-11/9 with an Anthony Smith style Suomi upper receiver. Magazine used is a Suomi “Coffin” magazine that holds 50 rounds of 9mm. No modifications or alteration of the M-11/9 lower receiver is required. Shotgun component is a NFA registered Remington 870 short barreled shotgun. BATFE letter was obtained confirming this is a legal configuration, prior to manufacturing.

The original Pulse Rifle was built off of a Thompson .45 submachinegun and SPAS-12 shotgun. In the film it was a 10mm caseless rifle with a 100 round magazine, and with a 30mm 4-shot grenade launcher. Considering there is the FRAG12 round out there, you could get darned close to the actual weapon…