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Manufacturer: Marushin (Japan)
Type: GBB

Marushin - Five-Seven USG, 6mm

Since my first AEG, an FN -P90, I've been interested in the 5.7x28mm round and anything that could be related. The FN Five-Seven (Named after the round, duh), is the first semi auto pistol to take this round. Marushin created the first replica of the USG variant and did quite a nice job appearance wise.

Marushin - Five-Seven USG, 6mm

Unfortunately, a decent airsoft GBB can't only rely on appearances alone... The overall build of this gun is plastic. Only notable areas of metal build are the magazine, outer barrel and firing mechanism parts (linkages, springs, etc). The overall weight of the USG is around 1.6 lbs, which most of that weight is in the magazine. The FN Herstal name was removed by "milling" out the plastic as seen in the above pic.

Marushin - Five-Seven USG, 6mm

I opted to go with the 6mm version, since 6mm is closer to the size of the 5.7mm cartridge. The 6mm carries 18 rounds, the 8mm holds only 10 rounds and the real Five-Seven holds 20 rounds. In the FPS results below you'll see that the 8mm has pretty much the same if not better FPS then the 6mm but if you take into account the weight and mass of an 8mm bb over a 6mm you can see the 8mm gun was designed to be more powerful.

Marushin - Five-Seven USG, 6mm

Some people saying that this Marushin product is a U.S. Import Version. While yes, technically if you live in the U.S. and you buy anything imported it can be considered a U.S. import version. The Marushin Five-Seven USG that is being distributed by Spartan Imports has NOT been modified/reinforced, like the U.S. import Versions of the Marushin M500, M1 Garand and M2 Carbine for higher pressure gas use.

Marushin - Five-Seven USG, 6mm

Take down is EXTREMELY easy. Unfortunately the hopup adjustment allen screw is hard to reach and does require removal of the barrel from slide to adjust.

Gas Usage Advisory!
Any Japanese Manufactured, Gas Blow Back Pistols are built to take 134agas, which is weaker then Green Gas. From my personal experience I found that Tokyo Marui, Western Arms and KSC GBB's can handle the more powerful Green Gas without problems. But for most other Japanese GBB's the use of the weaker 134a will insure a long, life. Use higher pressure gases at your own risk!

That being said... Of course I tested both 6mm and 8mm version on both 134a and Green Gas. Average FPS results below.

Update - 10/29/2007

Started taking the orange tip off the slide this morning, using the DW, Goof Off technique. Found out the plastic slide isn't made of the best quality because Goof Off started to melt the plastic of slide where the paint was being removed from.

Looking more closely into the plastic slide itself, it's a 2 piece slide. There was speculation at one time that the plastic slide was metal reinforced internally. It is 100% not. The slide has an internal plastic frame.

Marushin - Five-Seven USG, 6mm, Parts Diagram. Note the 2 part slide

There is also a feature that Marushin calls the "Real Indicator". It is an indicator at the rear of the slid that tells you if the internal hammer is cocked. Unfortunately it's extremely hard to tell what position it's in due to the fact its the same color as the slide and recessed in the slide. Diagram below shows how it works, it's just not as visible as the diagram portrays.

Marushin - Five-Seven USG, 6mm, "Real Indicator" Diagram

A curiosity of the 8mm Five-Seven is the use of a "bent" or "flatline" style of inner barrel in conjunction with a traditional hopup allen screw setup. That bend adding friction to the top of the bb, thus adding more backspin. The 6mm version does not have this bent inner barrel though, but has 2 hopup adjustment screws. Looking into more details regarding this.

Marushin - Five-Seven USG, 8mm, "Flatline" style Hopup