DMR Platform

I was thinking about building a DMR out of an m4/m16 body. Any one have any thoughts or ideas about brands? Also, any ideas about internals or external parts to put on the gun?

XUnJustEntropyX wrote:I was thinking about building a DMR out of an m4/m16 body. Any one have any thoughts or ideas about brands? Also, any ideas about internals or external parts to put on the gun?

KWA for the brand, you can never go wrong with KWA. Either the SR-10, SR-12, or M16BR. Externals are your own thing, but be careful what internals you use. Matrix Magnum, M130 or higher spring, Madbull Blue bucking, and an 11.1v or 7.4 lipo (7.4 depending on spring), and a mosfet will start you off. All of which Airdog carries.

Current generation KWAs are the only M4/M16 that I would dare build a DMR on. If you put a big spring in any other brand you WILL crack and break the front end of the gearbox.

a&k spr shooting 420:lol!:
or your choice of gun body and
modify gearbox
m170
matrix piston
bravo aluminum piston and cylinder head
type o cylinder
6.03 or 6.05 550 mm barrel
mosfet
matrix magnum motor

here is my 11 year old's DMR build:

JG m4a1
jbu 6.03mm TBB 509mm length (m16 length)
jbu suppressor to hide extended inner barrel (any length over 4 inches should be fine)
shs 14 teeth rack piston + guarder red poly head
solid cylinder (for matching barrel length)
gaurder o-ring nozzle
AOE using rubber washer on cylinder (prevents gearbox cracking)
chinese made cheap m150 spring (settled down to 480 fps)
or guarder sp150 spring if you want around 500-520 fps
madbull bucking with your choice of air seal mod (i use teflon, others use gasket sealant or dental floss)
AWS microfet wired to deans connector
7.4v 1800 mAH 25c LiPo + monitor
SHS torque motor

i kept the stock plastic cylinder head to further reduce gearbox fatigue
stock JG gears are strong enough for the m150 spring
use teflon tape to prevent any inner barrel movement
use the stock hopup nub because the madbull nub is bigger and will cause over hop.
use quality bb's. golden ball or g&g .30's are minimum. effective range with .40g is 200 feet. maximum distance is 250 feet (not that accurate).
to lighten the weight for my kid, i swapped the upper receiver with an a2 (permanent carry handle).
use your favorite scope (4x is adequate)

this build hasn't failed in a game yet and it was his first AEG.

-a|ex wrote:here is my 11 year old's DMR build:

AOE using rubber washer on cylinder (prevents gearbox cracking)

What is AOE?

XUnJustEntropyX wrote:

-a|ex wrote:here is my 11 year old's DMR build:

AOE using rubber washer on cylinder (prevents gearbox cracking)

What is AOE?

or if you use a reinforced gearbox, you can use two nylon washers (glued) with a longer screw between your piston body and piston head instead of the rubber washer glued to cylinder head.

Oh, okay. Thanks!

Just saying, I am trying to sell an M16 DMR. Look for my for sale thread, it is a really nice rifle and already has the work already done.

Twitch wrote:Just saying, I am trying to sell an M16 DMR. Look for my for sale thread, it is a really nice rifle and already has the work already done.

I don't have any money since I don't have a job. But I can do a trade if your willing.

Hi. I know I am new here but I'd like to share some information.

No, KWA's are not the best platform for DMR's!!

Sure they are great guns but as soon as you take stuff out of them you will see that they will slowly degrade. Add to that proprietary parts, you are screwed if something breaks.

First off, the gearbox should be properly modded to handle the springs power. You should radius the cylinder port corners, add 70d sorbo and a rubber pad on top to adjust AoE, use a plastic piston and head, and make sure your compression is good. After that is all set, you can begin with the hop mods. (I prefer to start with the hop mods, then the FPS stuff, it is cheaper and will give you better accuracy).

Choose a good bucking, preferably a harder one, and use a good nub. Generally I avoid hard nubs such as a plastic SCS, and prefer X nubs from Madbull fishbone bucking sets (don't use the buckings).

But to answer your question, a base gun can be anything as long as the externals suit you. I would stay away from KWA's as the price would limit your choice of parts. I suggest a JG, G&P or VFC.

i have put more rounds thru a high fps(530+)aeg sniper than anyone i know
probably more than 60k rds on the same set up with very little work
the last thing you want is a plastic piston head
kwa gen II gearboxes are super strong
if you start with a modify box like i did
you can spend more than the cost of a good gun on it($300+ in my case)
you can get 460+ fps with a stock kwa and a m140
you get what you pay for
you can build a nice sub 500 gun cheap
just dont shoot full auto and they hold up
the big thing is build it your self
that way you can maintian it
snipers are like hotrods and hot women
you do alot of work and you can play with them some
you cant drive a 6 second car everyday on the street
and selma hyake won't live in a single wide trailer
in the end build it shoot it break it and learn
just keep a backup gun so you can finish the game

logical wrote:

No, KWA's are not the best platform for DMR's!!

I just have this feeling...this feeling that...

Its about to go DOWN

Aggressor wrote:

logical wrote:

No, KWA's are not the best platform for DMR's!!

Its about to go DOWN

No, its just obvious someone doesn't know a lot about the 2GX gearboxes.

Alright, let me begin by saying that everyone is entitled to their own opinion. For the person above me, please do know things about me before jumping to conclusions.

KWA's...where to begin. I've owned at least 5, one that I managed to get 35 RPS out of, the rest just became boring and crap to me that I sold them off. The problems with KWA's are drastic enough to cause serious problems if someone were to do a DMR setup, or even a high ROF setup. First, the bearings; they will break under high load such as a M150 spring+. Since KWA uses 9mm holes, and that there are no readily available 9mm bushings out right now, you will have to continually see failures with the bearings, which may also cause gear failures, among other things.

Second, they use an aluminum piston head that is heavy and hard. Do not expect the front of your gearbox to last long on a powerful spring.

Third, their proprietary parts. The inner diameter of the air nozzle and the outer diameter cylinder head nozzle are NOT TM spec. Therefore replacement cylinder heads and air nozzles will not work, unless you plan on replacing all of the parts. Then you would have to replace the hop up unit, which there are no direct replacements for yet. KWA buckings are also thinner than normal buckings and are incredibly soft. They will shred at higher FPS'. With that said, KWA's chamber does not allow proper fitment of other buckings without modification. This can lead to problems with the nozzle not being able to push into the bucking all the way.

KWA also uses self shimming gears along with bearings which is their way of saying that their too lazy to shim. The gears will not mesh correctly, come stock with play, and will strip after a while. Best part about this is the gear axle placements on the gun are not TM spec, so increased wear is inevitable if you plan on replacing the gears. This is not too big of a problem if you use gears such as RiotSC's and a full steel rack piston.

This thread is devoted to figuring out the flaws of KWA's, everything wrong with KWA's are stated in here, I suggest you give it a good read before you splurge on a sub par performing AEG for above average price. http://forums.airsoftmechanics.com/index.php?topic=3550.0

As an old KWA fan I can promptly say that I never will be purchasing another KWA for retail price. Hopefully the trend that KWA is the best will fall off eventually.

Also, one more thing. KWA's trigger contacts are trash, the material they use corrode really fast. Here is the contacts after 10k rounds on a 7.4v 20C lipo.



And they claim it to be "lipo ready" for a 11.1v 1600mah 15c, but they don't even include a MOSFET!

you must have the worst luck lol because both of the kwa's i've owned work fine on 7.4 & 11.1 stock. do you just hold down the trigger or something?

After owning 5 of the same guns with the same problems I can easily conclude that this is not about luck but poor machining skills.

I am nicknamed by my friends as the ammo jew, I literally only do burst shots lol. But even if I did hold down the trigger, such a slow RoF should not give the gun any bumps after continuous firing, especially with proper shimming. I've dry fired my DSG P90 for 12 seconds when I had it just to see what would happen, and it just purred like a kitten. No hiccups or anything.

Aggressor wrote:

I just have this feeling...this feeling that...

Its about to go DOWN

.....died waiting for it to go down...

Lipo ready is such an understatement. Obviously you'll need a mosfet to effectively use a 11.1v Lipo, the term "Lipo ready" gearbox I think means that the gearbox externals can handle the advanced "wear and tear" a Lipo will create (faster ROF, more power pushed through the wires, etc). Nothing really is Lipo ready since I've never seen a stock gun out of the box that has a mosfet.

As for KWAs, I've heard that the SR12 in particular have a really high fail rate. My friend's SR12 stripped a gear in it's 2nd open game and a couple of KWA forum members have also experienced early problems with the SR12, but after they fixed this minor problem it performed smoothly. It's all personal preference. Anything can be a great DMR platform if built well.

Someone explain to me what Aggressor is saying ... If you are expecting a flame war please know that I did not come here to start one.

flipa, can you explain more how externals of the gearbox have anything to do with lipo usage? Because I'm not really sure what you mean. KWA's come with 16g teflon wire, good thing they didn't screw up there. That's good enough for an 11.1v depending on how much resistance there is in other places.

Ironically, some JG's come stock with fet's. You should also note that lipo ready is a very BROAD statement. I could say that my gun is lipo ready using a 7.4v 15c, which is somewhere in the area of a 9.6v.

Expected somebody to counter your argument. Everything opposing your point of view isn't flaming, FYI.

logical wrote:
flipa, can you explain more how externals of the gearbox have anything to do with lipo usage? Because I'm not really sure what you mean. KWA's come with 16g teflon wire, good thing they didn't screw up there. That's good enough for an 11.1v depending on how much resistance there is in other places.

Lipos bump more power and dramatically increases ROF. The faster the ROF, the more cycles your gears go through in a short period of time thus wearing down the teeth on the piston and the gears. I broke a piston head too. I guess it can't handle the stress of 35 RPS. It was a everything stock G&G combat machine with just a mosfet and a 11.1v 1800MaH 25C Lipo. Also the piston teeth were all worn to the point that it's almost nothing there.

logical wrote:Alright, let me begin by saying that everyone is entitled to their own opinion. For the person above me, please do know things about me before jumping to conclusions.

KWA's...where to begin. I've owned at least 5, one that I managed to get 35 RPS out of, the rest just became boring and crap to me that I sold them off. The problems with KWA's are drastic enough to cause serious problems if someone were to do a DMR setup, or even a high ROF setup. First, the bearings; they will break under high load such as a M150 spring+. Since KWA uses 9mm holes, and that there are no readily available 9mm bushings out right now, you will have to continually see failures with the bearings, which may also cause gear failures, among other things.

http://airsoft-club.com/shop/internal-upgrade/metal-bushings-shims/element-9mm-steel-ball-bearing-bushing

Second, they use an aluminum piston head that is heavy and hard. Do not expect the front of your gearbox to last long on a powerful spring.

I'm not a fan of the piston head they use because it is not ported. I have, however, kept it in my SR7 running 31rps with an M130 for 30K+ rounds. No cracks in the front. A polycarb P-head would fail before a crack appears in the gearbox with the current setup.

Third, their proprietary parts. The inner diameter of the air nozzle and the outer diameter cylinder head nozzle are NOT TM spec. Therefore replacement cylinder heads and air nozzles will not work, unless you plan on replacing all of the parts. Then you would have to replace the hop up unit, which there are no direct replacements for yet. KWA buckings are also thinner than normal buckings and are incredibly soft. They will shred at higher FPS'. With that said, KWA's chamber does not allow proper fitment of other buckings without modification. This can lead to problems with the nozzle not being able to push into the bucking all the way.

My hop-up has no problems with a systema bucking and I know Rhino has used a whole range of buckings with his battle rife.l

KWA also uses self shimming gears along with bearings which is their way of saying that their too lazy to shim. The gears will not mesh correctly, come stock with play, and will strip after a while. Best part about this is the gear axle placements on the gun are not TM spec, so increased wear is inevitable if you plan on replacing the gears. This is not too big of a problem if you use gears such as RiotSC's and a full steel rack piston.

Not sure what gears your's came with but mine are not self shimming, they just have no shims and the mesh perfectly.

Also, one more thing. KWA's trigger contacts are trash, the material they use corrode really fast. Here is the contacts after 10k rounds on a 7.4v 20C lipo.
And they claim it to be "lipo ready" for a 11.1v 1600mah 15c, but they don't even include a MOSFET!

Mine have held up for the life of it using nothing but 11.1v 1800mah 25C+ lipos. Of course, I have an AB MOSFET on it which I have on all of my AEGs because I use nothing but lipos. I would never NOT use on of my own MOSFETs with a lipo setup, whether it comes with with one factory or not. Generally the factory mosfets are trash.

Also, you don't have to come in here bragging about all the guns you have built. Let your work speak for itself and if it deserves praise then it will get it. Otherwise you just make yourself look bad.

poop cannon

flipa wrote:

logical wrote:
flipa, can you explain more how externals of the gearbox have anything to do with lipo usage? Because I'm not really sure what you mean. KWA's come with 16g teflon wire, good thing they didn't screw up there. That's good enough for an 11.1v depending on how much resistance there is in other places.

Lipos bump more power and dramatically increases ROF. The faster the ROF, the more cycles your gears go through in a short period of time thus wearing down the teeth on the piston and the gears. I broke a piston head too. I guess it can't handle the stress of 35 RPS. It was a everything stock G&G combat machine with just a mosfet and a 11.1v 1800MaH 25C Lipo. Also the piston teeth were all worn to the point that it's almost nothing there.

Yes but that is the internals, you said externals lol.

To Electioneer:

Those bearings you linked are bearings. Any bearings, especially low quality ones, are prone to failure in DMR setups. Link me a set of 9mm SOLID bushings.

Did you adjust the AoE and add sorbo to the front? That would make the front last much longer. I have a JG piston head in my DSG gun, and it has not had any problems whatsoever and is in pristine condition after 10k rounds of firing. Granted those numbers are not as high as yours logic implies that a heavier mass impacting the front of the gearbox will cause damage faster than a plastic one.

I actually have tried installing a Systema bucking into a 2GX hop up a while ago. The sleeve was too long and had to be cut to fit properly, and after that the gun would jam occasionally. I thought it was just the bucking and nub combination (SCS) but after trying a different one with a regular nub the results were the same.

Gears that do not use shims or are installed with methods other than using shims (such as VFC) can be considered self shimming in my view. If the gears mesh perfectly that's the bearings doing. I've had times where I needed to add .01 shims to make it run efficiently.

Where do you see me bragging about my gun builds? superchrisguy doubted my experiences with KWA so I provided some proof, showing that I have done some things with them, in no way was I bragging.