New DMR project, help with which base, what internals etc.

[joshh1512]

Hey guys, i'm quite fancying making a DMR, as i've been desperate to make my own project gun for a long time... so obviousley it's going to be locked to semi, and will be set to 425fps as that is my site limit (though i guess 420 would be better, as i believe that is the limit for most other sites).

Anyway... i'm thinking of basing it on an M4/16, or a SR25, however i need to ask a few questions first to determine which i go for...

1) What version gearbox does the SR25 use, is it v2 like the m4, or is it a unique box?
2) Again, is the hop up the same as in an m4, or is it unique to the sr25, as i would like to get either the madbull ultimate hop or the prommy stike...
3) Is the motor in an sr25 long type?
4) how compatible are sr25's with most m4 / m16 parts, ie.. will stocks, rail systems etc. fit on both?

So yeh, after those questions are answered, i'll of decided on which base i'm gonna go for, personally i'd like to go for the sr25 as i prefer the reciever even though it is only slightly different lol...

For the plan of the externals, i'll first be going for a tan magpul UBR stock, now is there much worthy difference between genuine magpul or a clone (if i can find a clone...PM if you know where to find one please).

SO..

External...

- Magpul tan UBR stock
- 12inch URX rail system (will this attach to an sr25 reciever)
- outer barrel.... i'll need help with this, if i'm using the URX rails, i gather they are freefloat, so how will the barrel attach to the body, and which barrel do i need to go for, i only want it to stick a few inches out of the rail, so i guess a 16inch barrel would be best, but do i need to have some sort of gas block or anything to hold it together, or does it just get clamped into place by the rails?
- Magpul tan pistol grip (will this fit onto an sr25 reciever?)

Now internals are another big factor...

If the gearbox is version 2, then this is what i propose...

- Element 9mm v2 gearbox shell (how does this compare to say a g&p gearbox, or anything else you would recommend? this would come with 9mm bearings, however should i change these and get 9mm bushings?
- M130 spring (is this gonna kick out too much fps? would an m120 be better?)
- SHS high torque long motor (should i go for a G&P m160 or m170 motor instead, and high torque motors give better trigger response don't they?)
- Gearset, which ratio should i be going for, and do i want high speed gears or max torque? any recommendations?
- Spring guide, element ball bearing v2 guide
- piston, SHS 15tooth (3metal) piston, will also correct AoE with sorbo pads
- piston head, Ultimate pom polycarb piston head
- cylinder head, Ultimate v2 head
- cylinder, Ultimate cylinder for sr16 (401mm - 450mm) is this what i need??
- SHS v2 tappet
- SHS v2 trigger block

Thats the gearbox done... hop etc next...

- Madbull ultimate hop unit or Prometheus neo strike chamber (which is gonna be better?)
- Element 'h'-nub (would it be worth getting the r-hop fitted professionally?)
- prometheus 6.03 barrel or madbull v2 6.03 (is it .03 i want, and which length will i need as i can't work it out?
- hop rubber, unsure of this,which will be best to go for at 420fps?

And finally i'm considering fitting a mosfet, however i'm worried i won't have room.... if i'm gonna be using a stock tube battery as i don't believe a battery will fit in the front rails, will a mosfet fit in the rear somewhere? IF so, i'll either go for an ASCU mosfet, extreme-fire, or a fireworks 'ares' mosfet, which will be the best performance wise in my case, i feel an ascu may be OTT?

alright, thanks for any help / input on what you guys think!

[humphriesryan]

Re: New DMR project, help with which base, what internals etc.

If I was you I would bas it of the m16 as the Sr25 has a long gated gb so it takes the same m4 hops tho lol, but if ur really wanting the g3 style mags then go for a Sr25 but if u don't care go for the m16 and get vn mags.
Spring wise il stick to the m120 kicking ruf 400 fps, as known you will stick a Tb barrel in witch will increase ur fps up so u should be hitting the fps Target u want about 415 fps, also if ur going with madbul hop go with there Tb barrel aswel as promethous barrel like being trubbel with the madbul hops and for length get 455mm standard m16 length for range and accrecey ( if u can do the r hop mod then its wirth it as ur firing above 400 fps and tht will also increase ur fps overall to 420 425 ish) ok u won't have any issues.
For internals ur going the right way just make sure u no what ur doing if u want any help talk to midas on her as he is the king of gbs ok .
Sr25 take the same motors as m4 and tht but one thing u will need to do is get a ab mosfet so it stops straight away and don't burn ur contacts lol again talk to midas about that he is in this forum ok .
( but if utter worried about space go with the Ascu 2 mosfet about 70 but there bril there the ones out of systemas, the mosfet is the trigger contact bit lop search it ) midas can get for ya
Hop rubber wise go with promethous hard or guarded hard there good and good airseals, and get a v or h shape nub it will put better spin on ur bb

[joshh1512]

Re: New DMR project, help with which base, what internals etc.

ahhh so if i use a v2 gearbox, then how will the hop situation work, if it will at all? i think an sr25 is gonna be complicated... do they use specific gears, piston, cylinder, and tappet? so i couldn't change those...

maybe an m4 would be the best base then, and i could get the g&p m4 sr25 recieiver, so i still get the trades i'm after etc...

is an element 9mm gearbox maybe overkill btw?

[humphriesryan]

Re: New DMR project, help with which base, what internals etc.

Yer ill go with the m4 base lol
An yer as long as it takes m4 mages the yer get that body if not then u might have to go with the Sr25 all it is, is a long gated m4 gearbox and I think the only thing dif is piston, cylinder, tappet and nozzle I think but don't hold me to that lol and just get a re-enforced gearbox ok

[Caveira]

Re: New DMR project, help with which base, what internals etc.

I'm not sure on their compatability with anything other than stanmag M4 based guns, but if you use the madbull hop go with the black python barrel and the madbull rubber as well. The individual parts are OK, but touchy, while together they are fantastic.

[joshh1512]

Re: New DMR project, help with which base, what internals etc.

Thanks Cav, so basically the 3 in combo is gonna be better than getting the ulitmate hop with prommy barrel? How about prommy strike chamber, prommy bucking and prommy barrel, that be even better?

And hump, it's a normal m4 reciever, but it has the sr25 markings on it, thats all!.

And what i'm saying, if the gearbox is just made longer, then wouldnt there be a big gap between the gearbox and the hop up?!

[jssmitty96]

Re: New DMR project, help with which base, what internals etc.

the sr25's have a longer piston and a longer v2 gearbox and the mags are a bitch to get go for an m16 few vn mags get a gearbox with a reinforced front end solid metal bushings + torque gears and then obviously you know everything standard will fit internals and externas

[joshh1512]

Re: New DMR project, help with which base, what internals etc.

I've found what to me appears to be an awsome package...

Basically, i get...

- g&p sr15 urx metal reciever (so i get the sr25 markings i'm after, but the m4 base i want)
- complete 8mm g&p gearbox with full internal set ready to shoot rear wired (great as i'll use stock tube lipo's)
- g&p m120 motor
- m16 pistol grip

And all of that is shipped for £120 to my door, seems outstanding to me! the reciever alone will cost £80 on it's own, for an extra 40quid you get a complete gearbox, motor and grip!

So anyway, if i go for this... whate are g&p gearboxes like? would it be worth keeping it, or selling it straight away and starting the gearbox from scratch and using an element 9mm? (so basically i'd get the reciever free once i'd sold everythign). How will the internals of the g&p box hold up if i put a m130/40 spring it in it to get 420 fps, i'd probably get a new piston and use sorbo to AoE correct it, would the gears be ok? anything else that would need looking at? And also the motor, would it be worth selling this straight away, and then getting a shs ultra torque motor, or even a g&p m170 motor?

What do you guys think, will love some input from you all!

[humphriesryan]

Re: New DMR project, help with which base, what internals etc.

Thanks smithy just wat I sed lol and no there would be no gap as smithy and me sed the front bits longer so it joins with the hop. lol

and if I was u get a re-enforced gb caseing as the gp ones are good for speed set UPs and any were up to about 350 fps set UPS but go any higher u will do what I did and split the gb front lol unless u use lots of dampers witch will reduce the impact but u will have to shave teeth of the piston and may reduce the fps

[joshh1512]

Re: New DMR project, help with which base, what internals etc.

no.. i meant if i used a standard m4 v2 gearbox in the sr25, then surely there would be a gap, if the true sr25 gearbox is longer?

Yes i'm gonna correct the AoE with sorbo pads, so which gearbox should i go for instead then? Surely if an a&k can run at 420fps, a g&p can?! Plus i'd change the bearings to solid bushings.

Oh, one more thing guys, i'll be wanting to fit a mosfet in there ideally, however not sure where there's gonna be room as i'll be using a stock tube battery, any thoughts what i could do? apart from buy an ASCU...?

Josh

[humphriesryan]

Re: New DMR project, help with which base, what internals etc.

Yer there will be a big gap u can't use m4 gb in a Sr25 body inlet its the one tht takes m4 mags and not The g3 style one lol

and the gp will take 380fps make anything more on a gp it will brake and the a&k ones are make out of stronger and heavier metal that's y they can handle more power, as gp make theres light so ur gun ain't heavy but makes the gb weaker ok

And for mosfets ur not going to be able as u def need one but the smallest is the Ascu but ur only option is to get a normal ab mosfet and stick a smaller bat in the stock tube or get a dif stock to take bats

[humphriesryan]

Re: New DMR project, help with which base, what internals etc.

Need any more help pm me looking would like to see the result at the end

[joshh1512]

Re: New DMR project, help with which base, what internals etc.

Thanks alot for the help mate, so basically, would you suggest going for the element 9mm gearbox? That's gonna be pretty tough isn't it? If not, any other suggestions? If i do that, how much of the g&p box could i use, would the gears, piston, cylinder etc. be ok? Or would you suggest getting torque gears?

If not the element, how about a 'modify' toros 8mm reinforced gearbox? If not this, whats gonna be the best for a high fps setup?
Edit: just looked around, and heard people running a gun at 540fps with the torus gun, and even 585 fps, it appears to me pretty strong, though would the element 9mm be better?

Oh, and what kind of barrel length will i be wanting (and will this affect which cylinder i need?) this is very important!

I'm basically after roughly a 12ich rail system, with an outer barrel that sticks out 3-4inches from the rail system, so it would be roughly a 15inch outer barrel, so what inner barrel would i be after?

thanks!

[humphriesryan]

Re: New DMR project, help with which base, what internals etc.

Either of them gb will be got (torus is better one) and no I would get torque stuff and gears , the gp gears will for for some time but not wirth screwing it up lol and go for a 450 mm Tb barrel and u will need a type 0 cylinder ok and yer cylinder has to match the barrel length or u will not get and compression

Type 0 (No hole): 450-580mm

Type 1: Systema makes this one, it has a hole in the edge and is said to be for M4/M16/XM177/AK47. It is essentially a go between for the type 0 and type 2

Type 2 (4/5 hole): 364-460mm

Type 3 (3/4 hole): 227-430mm

Type 4 (1/2 hole): 110-170mm

Hope this helps bud

[joshh1512]

Re: New DMR project, help with which base, what internals etc.

Well won't i be wanting the type 2?

What difference does it make may i ask mate?