Real Sword AK DMR build

[Cromulon1994]

Have you got a source for that? It'd be good to learn a bit more about it. 

Yeah, I'm an industry accredited asbestos surveyor. It's accepted lots of Russian plastics use asbestos fibres in their make up. Similar to bakelite type products did but It's not actually bakelite, it's more resin based. A mixture of chrysotile and amosite. 

You'd never know 100% unless you sampled a piece, there's a guy who lurks on here who knows more about the analysis side. 

 

[Adolf Hamster]

A bit late now but most Russian plastics like that have a healthy sprinkling of asbestos in their composition. I wouldn't cut any of them TBH. Same goes for mags and other furniture Russian firearms and launchers. 

there's my new thing for the day learned *looks at russian bayonet scabbard* note to self: never break that.....

I find myself name checked into this heresy I want no part of....*backs away slowly then turns and runs*

it seems like you're already committed as a conspirator......

You were warned ?

i suppose i was, balls of steel hacking up a brand new RS gun though.....

 

[Davegolf]

Had some random working hours recently but a whole lot of nothing hours! As I'm sure many have!

So things have fast forwarded a bit since last time, seeing as I'd ordered or recieved most parts in already it was down to me.

Gearbox time! Yes I junked 90% of the RS internals ?

This is most probably wasn't entirely necessary as with the whole of this RIF everything is so well made, as an engineer the fit and finish of the working parts makes me happy!

For RS information purposes;

MOTOR is conventional short type, it says hi-torque but it's not really on the grand scale of things.

Feels like 16tpa ferrite magnets.

GEARS are normal V3 style, with tappet delay chip as standard, they are very nicely made and the backlash between a fully installed set is equal to Marui - half to a third of a tooth in movement.

They were also shimmed very well.

BUSHINGS are 7mm bearings, good fit.

PISTON is unique, it has a relief at the back to clear the gearbox case and spring guide. It is nicely made from a fibre plastic, 2 metal teeth.

This looks pretty strong and doesn't really need upgrading unless your going higher than 450fps or are pre cocking.

PISTON HEAD is normal ported V2/V3, nicely made from a fibre plastic and has a ball bearing spring seat.

SPRING GUIDE is normal plastic but with a metal base plate. I kept this part in.

CYLINDER is a normal AEG full type '0' made of brass

CYLINDER HEAD is normal V2/V3 unit, not great and minimal shock absorbtion, probably the only let down part of the whole gun TBH!

NOZZLE is unique in length, it is nicely made from a strong plastic and is a very good fit and seal, to the cylinder head, rapper plate and bucking. I kept this part in.

SPRING mine shipped with a linear M120 with 26 coils - free length is 145mm.

BARREL normal AEG made from brass, assume 6.08 id, 455mm long.

BUCKING normal AEG, made from inner tubes it smells like hah! Really well moulded and tougher duro than usual, I kept this part as it was actually better than many others compared (Madbull, Prommy, PDI, G&G green)

HOP-UNIT usual sliding scale AK type, really well made, zero play very impressed. I kept this part in.

CHRONO'd at 410 FPS.

Regardless I wanted this to be the smoothest and most economical gearbox for power consumption, noise and joules - a DMR essential!

View attachment 55622

 

[Adolf Hamster]

That is some very interesting information, really it sounds like only the shell, trigger mech and piston are truly proprietary then?

Bodes well for upgradability.

 

[Davegolf]

Cheers, I think the trigger mech / trolley all looks normal, I don't have another V3 unit to check against, someone else may know for sure??

So yes to clarify, proprietary;

Piston

Gearbox shell

Poss trigger mech

Dont forget the nozzle ?

 

[Davegolf]

So gearbox got some new guts to go inside, I must say if all the standard gearbox shells I've seen these are so well fitting and nicely cast - no burrs or casting lines interrupting the piston rails etc, all the screws are actual proper threaded machine screws, the motor cage fitment is perfect and the bushing alignment is spot on!

The motor was swapped out to a 22000 ASG ultimate unit, I love these motors, so quiet and cool running.

The gears were swapped out for my favourite - a Siegetek 20.8:1 set including pinion - again the Siegetek bevel and pinion mesh is so quiet running.

Fitted and shimmed into SixG phosbro bushes.

Im using a 370mm barrel, so to volume match that to suit heavy ammo I swapped the RS cylinder for a Prometheus type 'B' along with a V3 Lonex cylinder head and Airlab sorbo.

I used a Retro Arms CNC piston which has a full steel rack, I had to cut the relief in the back to match the RS piston.

Both the gears and the piston rack required 1 tooth to be removed to match the RS gear tooth count, otherwise the gearbox would have turned itself into a big mess on the first trigger pull! Essentially trying to push the piston out the back of the gearbox shell!!

For the piston head I turned up a heavy weight stainless steel one for slowest speed build up and highest consistent energy.

For further weight the spring ball bearing assembly is also on the piston side.

View attachment 55801

Other than some some very minor titivating inside it all went back together.