Wanting to build a DMR, but have no idea where to start

[Jxmie]

Hello all,

I have been playing airsoft for a few months now and want to change it up a bit. I am looking to build a DMR setup, but have 0 clue where to begin. Not many airsoft sales websites have a DMR section for guns, and I have seen on a few forums that DMRs are built rather than bought. I have contemplated just buying one from the "Classifieds" section of the forum. But have decided to do it myself instead, as it will also give me some tech experience which will be useful. 

I was originally looking at a HK417 by umarex but have read and been told the gearbox housing can't withstand high FPS. and the TM 417 was just out of my price range (gun and upgrades). I am looking for something on the M4 platform 7.62x51. And have a budget of £500 or so for base gun and upgrades. And i am wanting around 400fps with .32bbs. If anyone has any suggestions for base guns and/or parts to get then i would be much appreciated as i have little to know knowledge about what brands are better than others etc.

 

[Steveocee]

DMR's require a budget similar to a BASR. There isn't much shortcut or "easy buy" for this kind of weapon unless you simply have a "hot" M4.

Good on you for not going down the M4 with a phat spring path though.

Good contenders would be like an AK SR25 or Cyma CM98 however both will still need about the same again if not more going in to them to make them tolerate the additional power AND be accurate at range.

My personal DMR is a foooking long M4 with a Kythera HPA system so it's easy to get the big FPS if needed but even then I've swapped out all the hop and barrel set up as well to get the accuracy I need.

If you are "only" aiming for 400 fps, honestly I wouldn't bother, just make a "normal" AEG up to about 340fps and then concentrate on consistency, hop up and inner barrel as the difference really won't be that much, I was running my battle rifle this weekend with 0.3's and I was ranging the DMR guy (who was at 400) and I had full auto capability.

 

[Impulse]

I hope you're not aiming for 400fps on a .32 as that would be 2.37J which is just over the limit for BASRs! You can run a "DMR" at 2.32J at some sites, but you'll need to have a 2 second delay mosfet installed as it's classed as a sniper.

For RIF, I'd say to get whatever you want and like the look of. Big props for not going with a big-spring-m4! If you like the ar-15 style platform, a Cyma cm098 would work really nicely. It's an SR-25, which is basically like an m16 in 7.62x51mm so it sounds ideal for you.

As said by @Steveoceeabove, you're going to need a decent budget if you want to make a great DMR. The cheap way to do it is keep it 1.14J and just swap out the barrel for a decent stainless steel one and the hop up rubber/nub for a maple leaf rubber and omega nub. This way keeps you with no MED, which depending on your site can be one hell of a boon, and can get some serious range and accuracy; it's how I've done my Cyma m14 build, partially because I didn't want to have to delve into that hot mess of a gearbox, and it fires to the envy of many airsofters and only cost me about £150 all in (it was bought before Taiwangun got Brexited). This is where I would start. £270 for the gun, £56 for a Prometheus 509mm stainless steel barrel (though honestly, the barrel doesn't matter too much. ZCI are a pretty good budget alternative), £10 for a Maple Leaf macaron or MR hop, £5 for a Maple Leaf omega nub all in will be around £340. These are the most important upgrades hands down; barrel and hop up are the things that will do most of the heavy lifting when it comes to achieving peak effective range and accuracy.

Now, going into a full DMR build you're going to need to up the power to whatever your local site limit is. Most sites are either 1.48J (400fps on a .2), 1.64J (425fps on a .2) or 1.88J (450fps on a .2) with an MED of either 20 or 30m. The way I would do it would be to go HPA because I'm a total HPA nerd and I always want to be as silent as possible, but that would add another £500ish for the build as you'd need the engine, tank, line and regulator, which would be out of your budget. Unfortunately I'm not that knowledgeable on AEGs as I've totally stopped using them now in favour of HPA and GBBRs, but I'll share my two cents anyway from my time when I used and upgraded them. What I'd swap out would be the piston, as you'll want a metal-toothed piston as plastic ones will strip the teeth pretty fast at higher powers, along with a new spring and a super high torque motor. If you have the budget, I'd replace the gears too. No idea what I'd put in, but that's the theory at least. i'm sure someone else can chime in with more useful advice as mine is mostly theoretical here as I don't use AEGs any more.

 

[Rogerborg]

I hope you're not aiming for 400fps on a .32 as that would be 2.37J which is just over the limit for BASRs! You can run a "DMR" at 2.32J at some sites

Beat me to it.  Please, please, don't set out thinking in terms of fps.  If your local site is still chronoing with 0.2g and talking in terms of fps, urgh, it's not 1999 any more.

My DMR shoots at ~1.8J with 0.32g BBs, I honestly couldn't even tell you what fps that is, as I don't need to know.

The first thing I'd buy is a chrono if you don't already have one.

but you'll need to have a 2 second delay mosfet installed as it's classed as a sniper.

Depends on the site.  My local just specifies one-in-the-air, and I've been asked once (and only once) to demonstrate that it's locked to semi.

On that, you will want to lock yours to semi, as anything capable of auto and over 1.3J is a Section 5 prohibited firearm, not an airsoft gun.

One easy way to do that is to file a little bit off of your selector plate so that it can't hold the cut off lever open.

View attachment 76663

The downside to that is that you won't have auto available to try and clear a jam.

Some folk put a screw in the receiver to stop the selector going to auto, although it's up to your site whether they'll accept anything that can be undone easily.

Mosfet based solutions are available, and a cycle-completion mosfet would help to avoid partial cycle lockups, although I've never had a V2 gearbox lock up on me yet running 7.4v lipo and a decent motors, even at 1.8J.

Big props for not going with a big-spring-m4!

*cough* Mk12 *cough*.

I agree though, with your budget and requirements, the Cyma CM.098 is the obvious choice.  Robust CYMA internals, QC spring, rotary hop. I wouldn't even change the barrel at first, just the fire selector, rubber (60 or 70 degree) and nub, then change the spring to get up to whatever your site limit is.  Run it with the stock 6.03mm barrel (clean it out first!) and see how you get on.

If you're still hankering to splash the cash, I'd then go to barrel (ZCI or AOLS, I've never tried Prometheus, Mad Bull or other high end stuff), and maybe motor depending how "high torque" the stock one really is.  SHS High / Ultra High Torque, or if you want to scrape every penny, the Big Dragon M160 from AliExpress is working well for me (and the M140s in non-DMR AEGs).

 

[BigStew]

If your looking at a 7.62mm Cyma do several SR-25s which some come factory locked to single shot. For a bit left field there are single shot AEG draganovs available. I personally don't like loosing full auto capability so can recommend a CYMA M14 great range out the box looks like a DMR but no lose of full auto, no minimum engagement distance so no need for a secondary weapon.

 

[Lozart]

If your looking at a 7.62mm Cyma do several SR-25s which some come factory locked to single shot. For a bit left field there are single shot AEG draganovs available. I personally don't like loosing full auto capability so can recommend a CYMA M14 great range out the box looks like a DMR but no lose of full auto, no minimum engagement distance so no need for a secondary weapon.

I second that! With a few minor tweaks you can be knocking on the door of DMR range AND still have full auto. I mean...I have three Cyma M14s so I may be a bit biased but even my M14 Socom gets comments like "is that DMR'd" and "that thing throws them way out there, doesn't it!".

I also have a DMR'd MK12 but the range isn't that much more for a lot more hassle in building it (although mine was built from scratch).

 

[Rogerborg]

The problem that I have with playing a DMR game with <1.14J AEGs is that if you like engaging at extreme range, then you'll want to use the heaviest BBs that your budget can manage, and I'm too cheap to auto-spam anything above 0.28g.  

I do agree that you're really not getting much extra maximum range, let alone effective range, until you get up towards 1.8J or so.  Even then you're talking maybe 10m, and if you don't have good consistency then you won't be hitting anything out there anyway.

 

[Lozart]

auto-spam

Just because you can, doesn't mean you have to.

If you spend the money on consistency and accuracy instead of chasing the FPS then you don't need to be shooting half bricks to get the range.

 

[Impulse]

The problem that I have with playing a DMR game with <1.14J AEGs is that if you like engaging at extreme range, then you'll want to use the heaviest BBs that your budget can manage, and I'm too cheap to auto-spam anything above 0.28g.  

I do agree that you're really not getting much extra maximum range, let alone effective range, until you get up towards 1.8J or so.  Even then you're talking maybe 10m, and if you don't have good consistency then you won't be hitting anything out there anyway.

For me it's a lot easier to decide. If I want to be engaging at extreme ranges, I'll just field my BASR with it's .48s at 2.32J, especially since the MED at my local site is 30m, the same for BASRs and DMRs (plus, my local site goes with 1.64J for DMRs, so with a 30m MED I just do not see the point at all). My local site gets pretty overgrown in late spring through late autumn, so while the foliage is like that I typically just go with the 1.14J "DMR" platform in my m21 because it's rare I'll be engaging at distances over 60m and I can hit 60m pretty damn effectively with my m21 build. Also with how thick the foliage gets I get a lot more encounters within what would be a 30m MED if I wanted to run something with an MED. It's all about where you play I think, as the other site near to me (that I'll be frequenting on the weekends Worthing doesn't run once I get myself a driving licence and a car!) has far more open sight lines and runs DMRs at 1.88J with a 20m MED, which would make me far more inclined to tweak the regulator to run my m21 as a DMR there. After all, there is a part of me that just sees an MED as an excuse to use my pistol more. I love my pistols and I make sure they can perform like a primary!

Just because you can, doesn't mean you have to.

If you spend the money on consistency and accuracy instead of chasing the FPS then you don't need to be shooting half bricks to get the range.

Yes, to an extent. Heavier BBs will typically be better, but there comes a point where you have to weigh up the miniscule increase in performance with the exponentially rising costs. I settle for .32s in my 1.1J "DMR" because they're affordable and seem to be pretty efficient at that power level. I still go through less than 500 in an entire game day when using my m21, but I'd rather shoot about £2.50 worth of ammo in 500 .32s than £12 worth of ammo in .48s every game day. The difference in performance is negligible. As soon as you start going to .36s or heavier, the price increases dramatically!

 

[Jxmie]

Please, please, don't set out thinking in terms of fps

Honestly, thanks for telling me this. Think a few others said this too. My airsoft sites website used to just say the fps limit for dmr is 450fps, they just updated it recently and now gives fps limits for different bb weights

My DMR shoots at ~1.8J with 0.32g BBs

Can i have some more info on Joule measurements, like what does it actually mean, how to calculate etc. I am thinking of running .32s myself.

The first thing I'd buy is a chrono if you don't already have one.

will definitely add this to the shopping list, thanks

barrel and hop up are the things that will do most of the heavy lifting when it comes to achieving peak effective range and accuracy.

Range and accuracy is the main thing i want, as my site is a big woodland so most of the time guys and gals are quite far away, so my current gun just can't reach them, or if they can the bb doesn't fly straight. We have a med of 30m for sniper and DMR, and most of the time people are probably 40m+ away (unless its towards the end of the game then they get very close). But most of the time enemies are at a large distance. 

the Cyma CM.098 is the obvious choice

I was looking at this on taiwangun, and i am planning on buying and building after christmas and was hoping they would be shipping to the uk by then as they are the cheapest. But i highly doubt they will, i found it on patrol base for £50 more but i think it was out of stock last time i checked. Is there any other sites you recommend to get the gun from? And also a good place to get internal parts from.

And finally do you reckon all of these things can be done by someone with 0 tech experience (all i have done is changed the motor on my current gun)? I have experience in messing around with electronics, is it something kind of similar in the fact that its just unscrewing things and swapping them out. Or is there a lot more to it than that?

Thanks to everyone so far for the replies, sorry if i take a while to reply to anything

 

[BigStew]

And finally do you reckon all of these things can be done by someone with 0 tech experience (all i have done is changed the motor on my current gun)? I have experience in messing around with electronics, is it something kind of similar in the fact that its just unscrewing things and swapping them out. Or is there a lot more to it than that?

Thanks to everyone so far for the replies, sorry if i take a while to reply to anything

it's not rocket science and there are many many gearbox building tutorials on youtube. just make sure you have a back gun before you take anything apart.

 

[Tactical Pith Helmet]

I personally don't like loosing full auto capability so can recommend a CYMA M14 great range out the box looks like a DMR but no lose of full auto, no minimum engagement distance so no need for a secondary weapon.

I resisted saying the same as I must sound like a scratched record, but 100%.

 

[RostokMcSpoons]

And Mr Neggy Airsoft would like to chip in with some swearing and an upgrade to a Cyma M14...

 

[Rogerborg]

Can i have some more info on Joule measurements, like what does it actually mean, how to calculate etc

Joules is the actual energy of the BB. This is the number that matters, for range, and impact on the target.  350fps with 0.2g = 313fps with 0.25g = 295fps with 0.28g = 227fps with 0.32g = 1.14J.

And you don't have to calculate it, because any chrono sold for airsoft use that you'll buy now will allow you to select your BB weight, and will tell you the energy in Joules, as well as the fps.

I am quite serious that I know the energy of my 0.32g BBs but I didn't even look at the fps number, because I don't have to as my local site chronos in Joules.

Not all sites do this, as they may find it quicker to look at the fps reading on the chrono and then cross reference it on a chart or cheat sheet, rather than changing the weight setting on the chrono each time.  It's really up to the site, my local sets the chrono and looks at the Joules number, some sites use a chart.  But even if they use a chart, the underlying truth is that they're applying the same Joules limit for every gun.