Shown here is a Kel-Tec PLR-16 chambered in 5.56 mm NATO, with a
Spyke's Tactical 37mm launcher mounted on it.

The PLR-16 has a conventional gas piston operation and utilizes the proven M-16 breech locking system. The rear sight is adjustable for windage. The front sight is of M-16 type. An integrated MIL-STD-1913 Picatinny rail will accept a multitude of standard accessories. The muzzle end of the barrel is threaded 1/2 -28 to accept standard attachments such as a muzzle brake. Except for the barrel, bolt, sights, and mechanism, the PLR-16 pistol is made entirely of high-impact glass fiber reinforced polymer.
The PLR-16 will accept any standard AR-15 style magazine.

PLR-16 Modifications:

This PLR-16 has been fitted with the bottom rail synthetic compact forend, an A2 flash hider, a slip on finger groove hand grip, and sports a 40 round AR-15 style magazine.
It has also been fitted with a Spyke's Tactical 12" STZ Havoc 37mm Launcher.

Custom Saiga 12 with launcher.

The Saiga 12 (aka S-12) is an AK-47 based 12 gauge semi-auto shotgun. The standard Saiga 12 configuration has the trigger group moved to the rear of the receiver, and has a plain buttstock with no pistol grip, similar to a conventional Remington shotgun.

S-12 Modifications:

Trigger group was moved forward to the original AK-47 location with Tromix trigger conversion parts, and a Hogue finger groove pistol grip added. The receiver was heavily modified to accept a Romanian under-folding buttstock. A tri-rail AK-47 receiver cover was modified and installed, along with a quad-rail handguard. Since the original 19" barrel is already threaded, a Talon Breacher muzzle brake was added.
This S-12 has also been fitted with a Spyke's Tactical 12" STZ Havoc 37mm Launcher.

Upcoming modifications will include a magwell and 20 round drum magazine.