MasterPiece Arms
MasterPiece Arms MPA Defender MPA57DMG
Semi-automatic MAC-pattern 5.7x28mm pistol, side cocking with a Picatinny top rail, 1/2x28 threaded, feeds from FN Five-seveN pattern magazines.
Key Highlights
- •MAC-pattern semi-auto host in 5.7x28mm
- •Picatinny top rail from the factory
- •1/2x28 threaded barrel
Specifications
- Price
- $647
- Weight
- N/A
- Calibers
- 5.7x28
- Rail Type
- picatinny
- Best For
- range traininghome defense
Capability Profile
0-10 Scale Across 8 Axes
Compatibility Tags
Overview
The MPA57DMG is the 5.7x28mm Defender: the same MAC-pattern straight blowback receiver as the 9mm MPA30T, rechambered and re-cut to feed FN Five-seveN pattern magazines. It is a serialized semi-auto pistol, not a registered machine gun. MasterPiece Arms lists it at $750, and Classic Firearms and KYGUNCO have carried it in the $640 to $650 range.
The two changes that matter against the 9mm gun are the cocking handle and the magazine. The 57DMG cocks from the side, which frees the top of the receiver for a Picatinny rail, so a red dot mounts without the aftermarket rail adapter a top-cocking MPA30T needs. It feeds from FN Five-seveN pattern magazines in 20 and 30 round capacities. Those do not interchange with the 9mm Defender's grip-fed magazines in either direction.
The barrel is threaded 1/2x28 and the gun ships with a muzzle brake. As with every blowback MAC, the action is not gas-sensitive, so a 5.7 can bolts on without any tuning.
Key Features
- Semi-automatic straight blowback action in 5.7x28mm
- Side cocking handle, which leaves the top rail clear
- Picatinny top rail from the factory
- Factory 1/2x28 threaded barrel, ships with a muzzle brake
- Machined aluminum lower receiver and aluminum grips
- Front and rear adjustable sights
- Feeds from FN Five-seveN pattern magazines in 20 and 30 round capacities
Pros
- +Picatinny top rail as shipped, so an optic mounts with no adapter
- +Threaded 1/2x28 from the factory and blowback-insensitive to a can
- +Takes widely available FN Five-seveN pattern magazines rather than a single-source proprietary mag
- +5.7x28mm gives flatter trajectory and less recoil than the 9mm Defender
Cons
- −Roughly $150 more than the 9mm MPA30T, and 5.7x28mm ammunition costs more per round
- −Magazines do not interchange with the 9mm Defender at all
- −Needs a rear stock or brace adapter before it is controllable at speed
- −Retailer stock is intermittent; listings go out of stock for stretches
Detailed Specifications
- caliber
- 5.7x28mm
- capacity
- 20+1 with the factory magazine; FN Five-seveN pattern 30-round magazines also fit
- Gas System
- Straight blowback
- trigger
- Single stage
- msrp
- $750
- handguard
- None; bare upper with a side cocking handle
- Muzzle Device
- 1/2x28 threaded barrel with a muzzle brake
- Receiver
- Machined aluminum lower receiver
- Finish
- Black Cerakote
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1 shared compatibility tags
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