Maruzen M870 custom parts
by Andrew Newton []

Stock Specifications
Model Remington m870 ABS stock
FPS 430fps HFC22 / 1BB
Length: 925mm
Weight: 2,200g

Ammo capacity:

4 + 1 shells

3-10 bb's per shell

M870 Review #1 | M870 review #2 | M870 review #3 | M870 custom parts review

Folding stock: I think the first thing one notices when looking at the M870 Grip Version is the folding stock. The folding stock I used was the Advanced Research Universal topfolding stock, which is meant to be used on a variety of real shotguns. Now, I think the Grip version has a mount on the grip to fit the Maruzen folding stock, and fortunately, this mount worked almost perfectly for the advanced research folding stock.

The only difference was in the design of the locking mechanism. On the advanced research there is a small latch that catches on the locking mechanism in the up position. On the maruzen, this latch caught a part of the grip, and was not able to fold out into the open position. So, I removed this latch with a Hack saw, and sanded it smooth.

I believe that the Advanced Research stock is a tiny bit narrower than the Maruzen stock intended to be used with the M870, but this worked out to my advantage, as the tight fit acted as a sorf of friction fit locking mechanism in either the up or open position. It takes a great deal of force to open and close the stock. And if the fit becomes loose, it's very easy to tighten the screw holding it all together.

Shell holder On top of this stock I placed the 5-shell holder, also made my Advanced Research. This particular shell holder was designed to be used with the folding stock, and therefor installation was a snap. It just screws right into the mounting holes already on the stock. And I think it adds a touch of class.

Heat Shield The second major part of this phase of the project was the heat shield. I don't believe that the Maruzen and the real remington M870 have the same dimensions, due to the fact that the heat shield fits a little too snuggly on the barrel.

One problem I had was that the fore grip rubs against the bottom of the heat shield. This friction caused the racking action to be a little more difficult, and would sometimes jam up the action all together. The racking action would also cause the heat shied to twist, and uncenter itself on the barrel.

To correct this problem, I took a steel grate, and sanded down the bottom of the heat shield. This takes a lot of patience, for the Advanced Research heat shield isn't made out of airsoft grade metal. It's meant for the real thing. But after a while, the heat shield fits snug against the fore grip, but still making it comfortable to rack.

A word of warning about the heat shield... when fitting the heat shield to the gun, it will scratch the finish off of the barrel. This isn't a problem for me, since I intend on leaving the heat shield on all the time. But for those who like a modular customized shotgun approach, be advised that your gun will look like crap up close if you take the heat shield off.

Here are some links where I got my info and purchased the parts: and

The end? And that's phase one of my "Ultimate, Badass Shotgun" project. I would tell you all of my future plans for the shotgun, but I don't want anyone stealing my ideas before I've implemented them, if you know what I mean. But I will definitly keep you posted on the outcome. (which will contain: lasers, flashlights, extended mags, scopes, sights, etc...). Until then, thanks for checking out my pride and joy shottie. by Andrew Newton []

External Links:


"Airsoft Base" :M870 review -the only English review I could find (Arnie)
Doraguner's M870 Riot version review - a review in Japanese
"Airsoft Guns in Russia" M870 review - a review in Russian

Other Interesting links:

Remington M870 Manual - The official manual for the real-steel Remington Pump action
SureFire Tac Mount - A Page with details of kits to mount Surefire lights and lasers onto the shotgun
Magazine Extension Kit @ ATI Gun Stocks - details of magasine extension tubes for the M870/M1100
Operator's Manual - the official US Government's operators guide to the M870
Custom Remington 870 laser mounting - a custom method for fitting a laser unit to the end of the 870, not a method I would recommend though.
"The Tactical Shotgun" - an article about shotguns and their use in a tactical environment. It's a VERY good read
The original website is from this page here: "The MultiPurpose Shotgun"

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Last modified: Wednesday, May 9, 2001 9:37 AM copyright 2001 ArniesAirsoft