TKOverKill

Prometheus springs for the AK blowback AEG series (version 9 gearbox) can be used in the M4 SOPMOD as is. They are shorter compared to "regular" springs.

Regarding muzzle velocitie, the guy at SEALs recommend an upper limit of 95 m/s at home. Home chronos have a tendency to shoot inconsistently depending on the state of the batteries. Another way to check for power is to use the ASGK plastic box with cardboard panels. It's not 100% accurate but will give you an idea on where your gun stands with respect to the chrono.

I used springs PDI140% for socom recoil shock (It's same Sopmod).
It can up to 365 fps but, I cut it to equal regular springs.

And if you want upto 400 fps. I recommend use spring from JG's gearbox or PDI150%.

Effective, my pistol's teeth is fail after use it. 555+

Now, I change to promethus pistol half teeth and modify to same as regular pistol for Sopmod.

I not recommend to use li-po battary 11.1V and speed ball not over 15 ball / second.

You can use regular battary 8.4V or 9.6V for Sopmod is better.

Does anyone know wether this RIS fits on the Sopmod?
http://www.gp-web.com/en/productspop.php?pid=1645

What I read, every airsoft RIS should fit, but not the barrels, so can I use this RIS with the standart barrel? Has anyone experience with this RIS in particular?

(The lenght of the standart barrel should be long enough that just the flash hider sticks out of the RIS, if I'm not mistaken)

Thank you!

p.s.: are any new custom or spare parts for the Sopmod in sight?


edit: I found out that I would need a 11,5 inch barrel, for this RIS, when I want just the flashhider sticking out, which sucks of course, as the only Sopmod barrel is 10,5 inch.
Is there any possibility to modify a normal airsoft barrel for the Sopmod?
Did anyone experiment with that yet?

(02-10-2009 08:55 AM)Vader Wrote: [ -> ]Is there any possibility to modify a normal airsoft barrel for the Sopmod?
Did anyone experiment with that yet?

Doubtful, as the construction is different. You will need a machine shop to modify the common M16 AEG barrel to fit inside a M4 EBB.

I suggest you either cut the stock barrel (it will still require a visit to a machine shop but will require less work) or use thread converters made by PDI to extend the 10.5 barrel.

Thanks! I didn't think of that.
Now i even found a Guarder barrelextension for Commando lenght, which is 11,5 inch =)

Hey there Vader, you mind showing me where you found that Guarder barrel extension? I've been trying to do the same thing as you for a 11.5 - 12 inch barrel setup. Thanks, any help is appreciated.

Hopefully I'm not too far off in piggybacking off this thread. This is really more for RON but for any others who are keen on a front Lipo battery in a small/slim RIS. My battery's from Air-borne and it cost Y3020/battery. It's a 7.4V 20C 1280mAh Lipo in a nunchuck design and I'm slipping it into a MB DD 9" RIS of my M4 Sopmod.

The Lipo battery with mini Deans connector :-



Comparison to an iPhone size :-



Amount of space I get to play with inside the RIS :-



And Lipo slipped into the RIS :-






Hope this is useful for others.

@Q
Thank you for sharing us some imformative pictures of the Lipo battery. Talking about Lipo more, there seems to be Lipo batteries that have TM type of connector. Heard that by Kenzie and those are probably as below.

http://triggertalk.militaryblog.jp/c9123.html

@RON yes. Actually my Lipo came with the TM type connnector (Tamiya connector). I actually cut and changed my connectors to Deans .

Q, could you elaborate on how you mounted your DD rail?

Zero,
When I tried to mount my DD rail it was fine except that the mounting hardware didn't get close enough to the receiver. As a result I never attached it, and put it on a Gas gun instead. That said, I think it would have fit if I had a couple barrel spacers.

By mounting hardware, are you talking about the bracket where the the rail actually is mounted to (which goes in place of the delta ring), or are you talking about the end of the rail itself, that's suppose to connect to the bracket?

I don't see how a couple of barrel spacers could bring together the rail and the bracket closer together, if the bracket bit is not close enough to the receiver.

If I recall correctly there are three parts in the DD rail, the mounting bracket that you screw the actual rail into (the one with the 6 holes), a piece that screws onto the receiver and holds the mounting bracket in place, and the rail itself (which is held onto the mounting bracket with 6 screws).

The mounting bracket goes on first, closest to the receiver, then the "holder" gets screwed on. As the holder gets tighter and tighter it holds the mounting bracket into place. If I recall correctly, this piece that holds the mounting bracket was loose as it wouldn't make positive contact with the receiver. If you added a few spacers this would allow it to tighten and would hold the mounting bracket in place.

Don't have the DD any longer so can't take pictures, but I hope that makes sense.

Sorry for the poor terminology.

Oh, I see. So if I put in something like... big washers from a hardware store, in between the receiver and the mounting bracket (The one with the 6 holes), then the securing "holder" will actually tighten up against the receiver?

Yup, that was the same thing with the G&P. Not sure to what specs Madbull made it for.