DMR build

[Chris#]

I will soon be purchasing a G&G CM16 R8-L with no upgrades with the idea of making it into a DMR.

I will be buying parts to upgrade it so that it has affective range, accuracy and an FPS around 400-450. parts I will be upgrading : Barrel, Stock, Hop unit, and Spring.
Has anyone got any suggestions of manufacturers or parts to use?

Thanks,

Chris

[rjb]

Re: DMR build

I will soon be purchasing a G&G CM16 R8-L with no upgrades with the idea of making it into a DMR.

I will be buying parts to upgrade it so that it has affective range, accuracy and an FPS around 400-450. parts I will be upgrading : Barrel, Stock, Hop unit, and Spring.
Has anyone got any suggestions of manufacturers or parts to use?

Thanks,

Chris

Chris,

Sorry to respond to your first ever post on Zeroin in what may seem to be a rather negative manner, but I suspect that you will disappointed with what you end up with if you go down the route that you have suggested. I presume that you have been airsofting for a little while and that this is not your first gun, so you are probably aware of the limitations of standard spec AEGs, but what you may not be aware of are the limitations and difficulties of DMRs. I was under the impression that going down the DMR route would transform my game, but it just doesn't!

From a technical standpoint, a DMR build is actually far more complex you might expect and what you are doing with your suggested upgrades is essentially building a high fps CM16 with a nice new stock presumably mechanically locked to semi... The key to a DMR build is consistency and therefore accuracy and the only way to get that is with a fair amount of work and skill. Whilst a new TBB or even a wide bore barrel might improve your accuracy, to get true DMR levels of performance, I reckon that there is probably a fair bit more that you need to consider.

For example, a full set of hi speed gears, a hi torque motor and MOSFET would be required to get the trigger response that is necessary with a beefy spring. Basically, without it, you pull the trigger and have to wait an eternity for the BB to finally leave the barrel!

You should consider dealing with the gearbox itself... 450fps means a big old spring in what is a old gearbox design. The v2 gearbox is prone to cracking, so that is something that needs to be addressed.

A standard hop up design may not cut the mustard, so you may wish to consider the R-Hop route - A potential nightmare to get it running the way it should.

Mods to improve overall consistency, airseal etc...

There should be a fair few topics on DMR, so have a mooch through Zeroin and see what you can find.

Good Luck

R

[Chris#]

Re: DMR build

Chris,

Sorry to respond to your first ever post on Zeroin in what may seem to be a rather negative manner, but I suspect that you will disappointed with what you end up with if you go down the route that you have suggested. I presume that you have been airsofting for a little while and that this is not your first gun, so you are probably aware of the limitations of standard spec AEGs, but what you may not be aware of are the limitations and difficulties of DMRs. I was under the impression that going down the DMR route would transform my game, but it just doesn't!

From a technical standpoint, a DMR build is actually far more complex you might expect and what you are doing with your suggested upgrades is essentially building a high fps CM16 with a nice new stock presumably mechanically locked to semi... The key to a DMR build is consistency and therefore accuracy and the only way to get that is with a fair amount of work and skill. Whilst a new TBB or even a wide bore barrel might improve your accuracy, to get true DMR levels of performance, I reckon that there is probably a fair bit more that you need to consider.

For example, a full set of hi speed gears, a hi torque motor and MOSFET would be required to get the trigger response that is necessary with a beefy spring. Basically, without it, you pull the trigger and have to wait an eternity for the BB to finally leave the barrel!

You should consider dealing with the gearbox itself... 450fps means a big old spring in what is a old gearbox design. The v2 gearbox is prone to cracking, so that is something that needs to be addressed.

A standard hop up design may not cut the mustard, so you may wish to consider the R-Hop route - A potential nightmare to get it running the way it should.

Mods to improve overall consistency, airseal etc...

There should be a fair few topics on DMR, so have a mooch through Zeroin and see what you can find.

Good Luck

R

From reading this, you obviously know your stuff I have been doing airsoft around 4 years, since starting I have never touched the internals of any of my guns. Through the 4 years I have been playing I have owned mainly m4's but I do own a couple of snipers (Well MB-07 and a 2nd hand TM VSR Upgraded) which is a pain as I am left handed, this is why I wanted to build a DMR.

When I am free I will spend time looking through some of the forums and take some notes, thanks for all the help.

Thanks,

Chris

[Horseman1]

Re: DMR build

Hi Chris,

I went down the route you are proposing - CM16 R8-L into a DMR setup.
Now I was incredibly pleased with the performance that the R8-L gave on it's first outing, no upgrades. Fairly snappy motor on single shot, good accuracy and range and an ok RD sight, all for a very cheap price.
Once I decided I was going to play around with the internals I did what was suggested above by "rjb" - Find as much information as you possibly can!
My advice though, if you're dead set on that gun, is play 1 game with it before you do anything. That way you'll be able to feel what might need improving, eg trigger response, power, range, accuracy etc.
As an example here's what I'm running in mine:
Systema M100 spring, Ultimate reinforced piston and Ultimate selector plate, SHS high torque motor (very crisp and quick), Madbull Ultimate hop unit with Madbull tight bore inner barrel.
All this is now in a Magpul receiver with Troy TRX rail so not even close to an R8-L anymore haha. However this gearbox has been very reliable in this setup for me.
A very good "base" gun for a build and you can always swap the externals when money allows. Just my 2 cents

[rjb]

Re: DMR build

Hi Chris,

I went down the route you are proposing - CM16 R8-L into a DMR setup.
Now I was incredibly pleased with the performance that the R8-L gave on it's first outing, no upgrades. Fairly snappy motor on single shot, good accuracy and range and an ok RD sight, all for a very cheap price.
Once I decided I was going to play around with the internals I did what was suggested above by "rjb" - Find as much information as you possibly can!
My advice though, if you're dead set on that gun, is play 1 game with it before you do anything. That way you'll be able to feel what might need improving, eg trigger response, power, range, accuracy etc.
As an example here's what I'm running in mine:
Systema M100 spring, Ultimate reinforced piston and Ultimate selector plate, SHS high torque motor (very crisp and quick), Madbull Ultimate hop unit with Madbull tight bore inner barrel.
All this is now in a Magpul receiver with Troy TRX rail so not even close to an R8-L anymore haha. However this gearbox has been very reliable in this setup for me.
A very good "base" gun for a build and you can always swap the externals when money allows. Just my 2 cents

Some good advice here. It might well be that you can get some of what you're after with the stock gun so, a least give it a couple of games to see how it performs. You can always start off making DMR type improvements such as adding a TBB and/or installing an R hop on your sub 350fps gun to see how things go. The bonus is that you get to keep the full auto 'fun switch'. R hops are phenomenal range wise, so you might think twice about installing a heavy DMR spec spring which really doesn't add much more range anyhow (see 'airsoft trajectory project' online for more on this). The real trouble with >350fps DMRs builds tends to start when you install heavy springs such as the m120 or m130 that you would need to take your gun up to 450fps. They tend to amplify minor inconsistencies (particularly with the hop) and put a hell of a lot of strain on v2 gearboxes which are a pretty poor design compared to say the v7 (M14) or even the humble v3. Just so that you know, version 2 gearboxes tend to crack at the front end at the end of the cylinder window, but you can help make this less likely by radiusing and adding sorbo to the cylinder head + a few other options.

Regardless, from what I gather, the CM16 is probably a good buy whatever you do with it...

R

[cheesenibbler]

Re: DMR build

From what I have had in the past, V2 gearboxes are ill suited for DMR builds, there are many things you can do to negate this however, I have had better results from the following:

V2.5 Gearboxes, the elongated gearbox, benefits over version 2 gb, less chance of cracking, larger volume in the cylinder, means heavier BBs do not need as high spring pressure to help propel the BB down the barrel, plus you can use a longer barrel with this extra volume if you so wish to do so (I stuck with a 509mm barrel and run 0.30s or 0.36s with great results, once i get a scope cam I will attempt to prove this!)
Bad points, some parts are propietary, such as the piston, tappet plate, cylinder, selector plate and one gear. Also you will need a heavier spring to bring it up to a higher fps, sounds like its contradictory to what I mentioned earlier, about spring pressure, however, have you ever tried sticking a M120 spring into a stock v2 gearbox? I personally find it a pain plus there is so much pressure on the spring in this, compared with much less pressure when installing the M140 spring in the V2.5 gearbox to acheive the same FPS.

V3 gearboxes, These are good gearboxes that sorted the problem with V2 gearbox cracks on high fps's plus if you are looking for consistancy then there is the added benefit on most v3 gearbox guns having a motor cage, this allows the motor to never really shift position when firing, the AUG is a good v3 gearbox to go with as its easy to work with due to being able to gain access to the gearbox easily, plus the hop up unit is the M14 style one which in my opinion is one of the best hop units out there. other V3 ones to look at, the AK, that has a very good hop unit too, not as good but still up there.

V7 gearboxes, (specifically G and G M14) this is a very good gearbox...if you can get get into it, thats a pain but this one has one of the most solid seals out of all the gearboxes between the hop and gearbox. But I wouldnt want anyone working on this without prior experience with v2/3 gearboxes beforehand.

The other one is the TM PSG1 gearbox, the V4, this one is a fairly expensive buy but has a great hop unit and great internal build.




The other thing to look at is a hop up that gives a nice even distribution on the BB, a regular hop nub does not do this as this is basically a barrier between the bb and the barrel, there are a few hop rubbers that do give a much more even spread on the BB, I have noticed funily enough in my GHK G5 that I have the hop rubber is flat and long inside the window, this gives it surprisingly good range and accuracy for a gun firing only 300fps with a 200mm barrel, It was firing further then anything the opponents had at the time and this was at ground zero weekender on a long straight corridor!

There is so much that needs to be looked at regarding DMR builds, I have found a lot of it to be trial and error, I ended up with putting a AUG nozzle inside my AR10 which only had a M4 type nozzle originally and this in itself increase the FPS (415fps with a 0.20g, consistancy (5fps deviation) and range all in one go, wouldnt have thought it based on just a nozzle change but it did!

If you are going down the route of the combat machine m4 I would personally do the following:

High torque motor (SRC high torque are imo very good for the price they are very snappy on a 11.1v battery with an M120 spring this motor is built for torque)

New gears (possibly this is dependant on if you are confident with the current ones, the CM gears are pretty decent standard but it maybe worthwhile looking at guarder)

New bushings (this is a must the stock bushings on the CMs are rubbish brass things that melt and warp) Steel Bushings are suitable I wouldnt put bearings into anything torquey above an M110 as there is a wider tolerance.

Piston Look for pistons with the second to last tooth missing and dont be tempted by the full metal tooth pistons, the teeth tend to fall out or shred the gears.

New cylinder, any brass or steel cylinder is better then the rubbish aluminium one in these, also another thing, I have done a few experiments with different cylinders (full type 3/4 and half) and depending on the barrel length if you lets say put a full cylinder on a MP5K barrel you will loose FPS so make sure you suit the cylinder to the barrel.

Cylinder head and piston head silent type systema, this one helps with the pick up on the piston as well as reduces overall stress on the gearbox due to a larger surface area being hit by the piston.

Nozzle, this is experimental you need to find something that pushes the BB solidly just behind the nub and puts a good seal on the back of the hop rubber.

The hop unit, the CM hop units IMO are not good, they tend to apply a very short amount of hop aggressively giving the impression that its working well but does not give particualy good range, look at the Madbull 3 in 1 type hop unit or even possibly a guarder type, these units have good response and are not aggressive.

The hop rubber, this is again up to you, everyone on every forum I have looked at screams R Hop, however I have not seen anyone with an R hop set up in a game get any huge advantages in range with an AEG, its only worthwhile if you have an AEG firing over 450fps with a 0.20g bb, its very aggressive and produces similar traction as a flat hop, its perfect for the american market due to the high fps's they run but only really good in sniper over here. I like hop types that fill up the hop window without being too intrusive. PDI do a good hop that doesnt wear down and gives good consistant results, firefly do a good hop rubber that is very long which is good for high fps setups.

I am sure someone will say differently about the R hop being amazing super consistant etc but it seems like a very time consuming setup with a small amount of gain.

The barrel, again this is up to you, I like heavy barrels personally as I find there is less deviation especially in high FPS set ups as there is less wobble. I have taken to using the Madbull Steel Bull Barrel mainly because these ones are very heavy, theyre a bit cheaper then some barrels out there, are machined (so far as I can tell!) very well and so far have produced excellent results. There is one other barrel i would say is very interesting, its called the Tanio Koba twist barrel, you need to have a low velocity set up (less than 320fps on a 0.20) for it to be to its highest potential but these barrels since I tried using one have proven to be very impressive, bad points the BBs are affectly massively by wind and even slight deflections on grass or leaves but have one of the straightest and most consistant trajetories I have seen in a barrel upgrade. I might try another one in one of mine to see what I end up with just for fun!

Those are the parts I would definately look at to change if I was looking at the piece you have.