Advice on version2 gearbox for sniper

Ebr sniper

I've a custom built g&p sr25 sniper almost built but I'm not sure what the best gearbox would be for it. I'm looking to keep it realistic so a good semi auto gearbox is a must. Am I better off buying a good high torque gearbox or should I buy the parts individually and assemble a custom gearbox as well. What do you all think? Thanks

NakedDex

Is it actually an SR25, or is it an SR15? In other words, are you using a proper SR25 receiver, or just an M4/16 receiver and calling it an SR25.

I'm not just being pedantic for the sake of it, but DMR rifles like the SR25 are chambered for 7.62, so the receiver is much larger. Genuine SR25 bodies are too long to take a standard V2 gearbox. You need a particular type made for that exact receiver. The V2 will fit, but there'll be a couple of inches of a gap between the nozzle, barrel, and mag.

Ebr sniper

I have the sr25 reciever but no gearbox so I've been using a g&p m4 reciever as I had all the internals pieced together and ready to go. I'm going to stick with this reciever as I prefer the look but at some point I will put the proper sr25 reciever on. So advice for now is on an ordinary version 2 gearbox in an m4 reciever. Oh and anybody know where I could get the longer gearbox for the sr25 reciever. Thanks

Southern Dandy

Ebr sniper wrote: »

I have the sr25 reciever but no gearbox so I've been using a g&p m4 reciever as I had all the internals pieced together and ready to go. I'm going to stick with this reciever as I prefer the look but at some point I will put the proper sr25 reciever on. So advice for now is on an ordinary version 2 gearbox in an m4 reciever. Oh and anybody know where I could get the longer gearbox for the sr25 reciever. Thanks

Far as I am aware the Lonex gearbox with an extended SR-25 air nozzle would work, having said that it might be a G&G SR25.

Have a look on UNCOMPANY for gearboxes shells I'd swear I seen them and some of the proprietary parts for the SR25 V2.5 gearbox.

NakedDex

So what you're looking for is a receiver for an SR15, which is a basic V2 box. If you're using it for a DMR style build (wouldn't be a sniper build, way too loud), then go get a decent shell and build one up to suit. Pick and choose your parts to get maximum performance. If you're aping the SR25, then you'll only be firing in semi, so get a high speed motor on a MOSFET to increase your trigger response and cycle time (lower cycle times mask perceived noise, as well as giving a snappier performance). Pair that with a decent shell, high torque gears on bearings, and splash on a silenced piston head if you really want to give yourself a fancy box. You can lock the selector with a roll-pin and a 3mm drill bit to stop pushing on past semi into auto, too.

G&G do a replacement long-box V2 for the SR25 they make. I *think* G&P have it available to. It's a complete gearbox, and be aware that they're rocking longer pistons/cylinders etc too, so spares are specialised.

CpcRc

Or you can cut a bit off the selector plate so it can't engage full auto anyway. Remove the piece that pushes the cutoff lever when switching to auto. I think that's what someone did for a dmr for a milsim so it wouldn't be able to go into full auto and would pass dmr regulations.
Just a cheap suggestion.

Inari

This is where you're going to get a lot of different opinions on set ups. Personally what I would do if building a DMR is:

- 8mm Gearbox shell (G&P, Lonex or Supershooter would be my main choice)
- Low-ratio (i.e. high speed) gears; 13:1 would be my first choice
- 8mm ceramic bearings glued down (you're not going high ROF; much lower risk of collapsing - reap all of the benefits of using bearings)
- Air seal parts (stick with the same brand for Cylinder, Cylinder Head & Air Nozzle - each part will have been designed to work with themselves, and so tolerances are in your favour)
- Hair trigger mod (found here
- M110 Spring (Short stroked by 4 teeth)
- Bearing spring guide
- Plain-ole piston head (vented)
- Swiss-cheesed piston (i.e. drilled to fook-zilla!)
- MOSFET (preferably one with pre-cocking)
- Sector chip (also known as a gear delayer)
- Correct the Angle of Engagement
- 11.1v Lipo
- Neodymium magnet high torque motor

I'd put in a wheel based hop up unit, with an IR-hop (with M-nub), using a Prometheus barrel 6.03 - I'd probably use a 363mm with a Madbull Gemtech Halo silencer, rather than having the longer barrel hidden in the silencer.

What all of the above does is give you a short & light trigger pull, as well as a ridiculously quick piston return time (stronger spring), and quick cycle (lightweight piston assembly). The MOSFET prevents/reduces arcing on the trigger contacts, as well as providing some more advanced features if you go for the likes of the Chimera, Spectre, Raptor or MERF 3.2 etc such as the pre-cocking ability where the piston is retracted 75% of the way, so when you press that lightweight trigger the effect is immediate. The combination of the neodymium magnet high torque motor and higher voltage battery results in a much lower spool time for the gun to cycle, further improving your ability to put shots down range immediately after pressing the trigger.

It also makes the gun quieter in a sense - the cycle is finished much faster, and as such it is harder to pinpoint where the sound came from