MasterPiece Arms’ MPA5700sst: the Defender 5.7×28 Carbine

MasterPiece arms, manufacturer of Defender MAC (Ingram)-style pistols and carbines, has announced a new carbine chambered in 5.7x28mm, the Defender MPA5700sst, the high-velocity pistol and submachine gun cartridge developed by Fabrique Nationale. This follows the release of a Defender pistol chambered in the same caliber early this year, the MPA57sst.

The Defender is loosely based on the MAC (Millitary Armament Corporation) M-10, also known as the MAC-10. It makes some changes to the design to modernize it, specifically moving the top charging handle to the left side of the receiver and replacing it with a Picatinny rail for optics. It maintains the indestructable adjustable M-10 iron sights.


The grip of the MPA5700sst carbine is far removed from the original designed by Ingram. It’s an angled grip designed to accept standard FN Five-seveN magazines; it ships with one 20-rounder but will also accept aftermarket 30-round magazines.

Fitted with a low-profile tube-style AR fixed buttstock and aluminum quad-rail handguard, the MPA5700sst is ready to go for any accessories you could want on a 5.7x28mm carbine. It also features a custom muzzle device, a combination flash-hider/compensator. The barrel is threaded ½×28 for other muzzle attachments, and gives the MPA5700sst an effective range of about 200 meters.

FN Five-seveN Magazines and Ammunition

Other specifications of carbine are that it has a 16-inch barrel, and overall length of 34.5 inches and it weighs about 6.5 pounds unloaded. The MPA5700sst has an MSRP of $795 and should retail for around $600-650, which is a huge savings over an FN PS90 bullpup, and a good thing when you’re an enthusiast of the not-particularly-budget high-speed low-recoil 5.7x28mm cartridge.

The MPA57sst is also considerably less expensive than a Five-seveN pistol, with an MSRP of $600, which is less than half of the Five-seveN’s MSRP of $1316.

MasterPiece Arms’ guns ship in a custom gun case and have a lifetime warranty. For more info on the MPA5700sst and the other Defender pistols and carbines chambered in 9mm Parabellum and .45 ACP in addition to 5.7x28mm check out their website.

Photo credit forensicaldude.