Hi all

I have just finished attaching my SPAS 12 cage to the TM Thompson. What I would like is some advice on attaching the hand grip to the M870.
I have shortened and installed a Maruzen M870 BV (this is the gas shell ejecting M870). There are two metal bars which slide backward and forward to rack the gun. I have made the cuts in the SPAS cage but these bars need to be shortened. I can't cut them at the ends that go into the receiver as they are shaped to fit etc and at the front end they bend up slightly so that the two holes in the ends are inbetween the upper and lower barrel. It is at this end that I will have to make some mods.
I'm sure other people will have done this themselves already and would appreciate and advice that can be offered as I don't want to learn by trial and error on this as the parts are kinda difficult to replace if I make a mess of it.

So to sum up I need to know how to shorten the two bars for racking the 870 and then the best way to attach the hand grip to these.

Thanks in advance for any help that can be offered.

Cheer

Darren

Darren, if you can take a pic it will help immensely.

You don't want to cut the back of the bars as they're specially cut to work the mechanism within the reciever. so you'd need to cut the front of the bars. If you take a pic of the action slide assembly on its own, and another pic with it mounted on the M870, I can give you better advice.

-Alex
"The M41-A. When you absolutely, positively have to kill every mofo in the room. Accept no substitutes."

thanks Alex

I'll post some pics but probably won't be able to until Sunday unfortunately as I'm away this weekend so I've only got the laptop.

Cheers

Darren

I'll try taking mine apart (again) this weekend and measuring the arms.

Like Alex said, youll want to cut off the front end, not the part where it goes into the receiver.

Also, you should put your M870 in the Spas cage to measure which row of bars to sut out of the side to allow the Spas mount bolt to go through. The real steel and SD studios versions are actually one row below where I had to cut mine so it lined up.

I haven't actually mounted the sleeve or the arms for the action permanently yet. Still trying to make a permanent decision regarding the sleeve mount.

Russ



"Time has little to do with infinity and jelly doughnuts."

Hi Guys

Here are some pics

This is the M870 with the bars fully extended. There is a faint black line where they need to be cut back to.

[img]http://www.friendly-skies.co.uk/public_html/M870a.JPG[/img]

This is the M870 inside the SPAS cage with the bars extended.

[img]http://www.friendly-skies.co.uk/public_html/M870b.JPG[/img]

Here the bars are retracted. As you can see the cuts that I made before I got the Maruzen are lower than the bars.

[img]http://www.friendly-skies.co.uk/public_html/M870c.JPG[/img]

And finally here it is with the grip in place. The attachment holes on the grip line up with the lower set of holes on the cage. So something will have to go through the cage and then up slightly to fix onto the bars.

[img]http://www.friendly-skies.co.uk/public_html/M870d.JPG[/img]

Any ideas?

Cheers

Darren

Hey Darren,

I'm going to start on my pulse rifle soon. It's an SD Studio parts set and a M870 as well.

It looks like you may have to fashion some sort of metal bracket to extend the slide bar to where you made the slots.

By the way how much did you cut down your maruzen barrel to?

Hope my idea helped.

Gene

Hi Gene

The barrel is just over 6 inches long. I can get more precies measurements for tomorrow if you want?

I'm getting some ideas on how to proceed. I have now cut the slide bars back to the required length. I have to drill some new holes in the ends.

I'm thinking of using the original u-shaped piece which attached the two bars originally and then screwing into the side of this piece through the hand grip. This will ensure that the two bars slide in unison.

Darren

Hi Darren,

Here's my suggestion:

Create a metal plate and bolt it to the action bars. Making the plate a U shaped bar is also a good idea, and is essentially how a real steel action tube works.

[img]http://www.hooverae.com/upload/pics/GL-Plate1A.jpg[/img]

Drill two holes into the metal plate so that it matches up with the slot you've cut, and also with the holes in the SPAS12 grip.

[img]http://www.hooverae.com/upload/pics/GL-Plate2.jpg[/img]

This way it should look aesthetically accurate to the Hero rifles, and at the same time, function correctly.

-Alex
"The M41-A. When you absolutely, positively have to kill every mofo in the room. Accept no substitutes."

Cheers Alex

Thanks for the ideas. I have gone with the u shape bracket however as I have the pieces already. The benefit of using this is that it bridges the two slide bars and makes sure they slide together. I drilled two new holes into the side of the bracket which was a bit tricky as it is a curve obviously and then tapped them. I'm just waiting on a new hand grip now. I've used the one I have to test fit the pieces and slide action and it's all pretty good. The sound is sooo much better now than plastic on plastic.
I have also added a gas inlet on the side of the pulse rifle. There is no room inside for a gas reservoir so when skirmishing I will mount this externally and attach to the inlet.
I put the inlet on the opposite side of the counter as I am right handed and this means it will be facing my body and therefore less noticeable.

Thanks again for the suggestions.

Darren

Hey Darren,

Let me know what the exact measurement over 6 inches it is.

Thanks!
Gene

First of all let me say "hello" to you guys...

I´m a long time lurker of the board, who was infected with the PR virus by Tom aka nimmot

I´m in the process of building my own PR and this tutorial comes handy, THANKS! I´m using a real deac. 870, along with real SPAS cage and I am also interested to know how long -exactly- the barrel has to be.

Thanks in advance, Markus

Hi Guys

I'll measure it tomorrow for you but please note that I am using a Maruzen airsoft M870 and not a real one so there may be a difference in how long the barrel should be depending on any difference between the length of the airsoft receiver and the real one.

Cheers

Darren

The best way to deduce how long you want the 870 barrel to be:
* insert the 870 into the SPAS12 cage
* make sure it's in the correct position
* slide the Front Grenade Launcher block onto the 870 barrel until it's plush with the SPAS12 cage
* and mark off the barrel at a point that is about 5mm or 1/4" extended beyond the front of the block (whatever amount looks best to you personally).
* and cut from there.

Remember it's always easier to cut off too little than too much. You can remove more material later on, but you can't really add to what you've already cut off. Some people like to extend the barrel really far out of the front block. Personally I like a more snubbed look to the Grenade Launcher and only extend the barrel out by about 1/4" at most.

-Alex
"The M41-A. When you absolutely, positively have to kill every mofo in the room. Accept no substitutes."

Darren: I have a Maruzen M870

Alex: Great tips! Will keep this handy when I am doing mine.

Gene

Hi Wick

The upper barrel on mine is 6 and 4/16 inches and the lower is 5 and 14/16 inches.

Alex's advice above is the best option though, that is how I did mine.

Cheers

Darren

Darren,

Thanks so much! I agree Alex's advices is the best one.

Gene