Manufactured in West Germany in 1986 as a semi-automatic carbine, and then converted to full automatic by David's Gun Room of Norcross, Georgia, this is a selective fire closed bolt submachine gun made in emulation of the "Schalldaempfer" integrally silenced variation of the famous MP5 submachine gun. Prominently associated with operators like the U.S. Navy SEALs, the SD used a combination of a ported barrel and integral silencer to achieve subsonic performance from military standard ammunition. This example uses a more modern detachable silencer (more details in Item B description), but does retain the original barrel porting, a feature commonly overlooked in American SD conversions. Hooded post front and four-position drum rear sights, with a ribbed heat shield forearm, "MP5 SD HK" markings on top of the receiver (partially obscuring the David's marking), textured ambidextrous pistol grip and fixed buttstock. The magazine well has been altered to restore the original "hinge pin" configuration, complete with functional paddle release. The bolt carrier is a semi-automatic unit with a professionally built-up sear trip, with a "hinge pin" style ambidextrous trigger pack with full auto, 3-round burst, semi-automatic and safe positions, and corresponding pictographic markings on the housing. Included with the lot are nine extra magazines and a side-folding buttstock.

Measuring 12 inches long and 1 5/8 inches wide, with a mesh-filled expansion chamber in the rear and baffles up front. Compatible with A, enclosing the barrel and being partially enclosed in turn by the forearm.