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dmr build help! long range aeg
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Airsoft_Newb

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Discussion starter · #1 · (Edited)
MY First DMR Build

Hello All,

I am building a DMR, as the title says, and this is my first long range AEG build. I would like some assistance in the build parts wise.

No, I will not attempt R-Hop but I do know how to flat hop and many other DIY modifications.

I have no strict budget. My base gun is the Echo 1 Troy M4 7in.

I am fully confident in my tech know-how as far as taking apart and rebuilding the whole gun.

I would like 300ft+ of range and under 500fps.

Help is much appreciated!
Thanks to all of you!
 
#2 ·
Airsoft_Newb said:
Hello All,

I am building a DMR, as the title says, and this is my first long range AEG build. I would like some assistance in the build parts wise.

No, I will not attempt R-Hop but I do know how to flat hop and many other DIY modifications.

I have no strict budget. My base gun is the Echo 1 Troy M4 7in.

I am fully confident in my tech know-how as far as taking apart and rebuilding the whole gun.

I would like 300ft+ of range and under 500fps.

Help is much appreciated!
Thanks to all of you!
Click to expand...
First of what is your budget? Second have you read this: http://www.airsoftsniperforum.com/43-longrange-aegs/892-holy-grail-building-your-dmr-aeg.html

The gun looks nice and Echo1 makes great guns. I would look to extend the inner barrel to 400mm- 455mm but that is personal preference.
 
Discussion starter · #3 ·
#5 ·
Airsoft_Newb said:
Also my stock barrel is a 250mm. What upgrades would I need to do to get it to 455mm besides the barrel itself.
Click to expand...
Have you found or looked for barrel ratio charts? Also you would need to either get a barrel extension to but that won't get you to 455mm or you can get another outer barrel to take a longer inner barrel. Another question do you own the gun already?
 
#7 · (Edited)
Airsoft_:-) Newb said:
First of all, yes I do own the gun. It's a Echo 1 Troy M4 7in. I was looking for outer barrels and found one that will house the 455mm barrel. Just looked at a barrel ratio chart. It appears I want a Type O cylinder(No holes).
Click to expand...
That is correct, you will want a type 0 cylinder. Make sure you get an m130 spring that is not irregularly pitched, those tend to put out more FPS than a normal m130 spring. So my guess is you want to be shooting around 450-490 max? If that is the case you need to consider disassembling the gun and checking out some of the GB internals to see what you are working with. Do that before you get into upgrades.

Things to look for:
1)Does the cylinder head and piston head make a good air seal?
2)Is the spring guide metal?
3)Does the spring guide and piston head have bearings?

Things to ask yourself:
Do you want to go with a LiPo battery?
What is the max bb weight you want to use?

Things I would consider upgrading without even opening the gearbox:
1)Piston: Lonex Red Piston
2)Motor: Lonex High Torque Motor
3)Gear set: Matrix 32:1 or 18:1, Lonex, G&P, Prometheus
4)Inner Barrel: Prometheus 6.03mm
5)Bucking: flat hop
 
Discussion starter · #8 ·
What are these bearings you speak of on the spring guide and piston head? I haven't heard of the Lonex brand before; I'll look into them. As far as flat hop goes; would the Modify flat hop work? I've also heard you can take sand paper to the G&G Green and then use the firefly bucking with a roller bar. Opinions?
 
#12 ·
Airsoft_Newb said:
What are these bearings you speak of on the spring guide and piston head? I haven't heard of the Lonex brand before; I'll look into them. As far as flat hop goes; would the Modify flat hop work? I've also heard you can take sand paper to the G&G Green and then use the firefly bucking with a roller bar. Opinions?
Click to expand...
These are the bearings I am talking about: ASG Lonex Ultimate Upgrade Steel Spring Guide with Ball Bearing - (Version 2), Accessories & Parts, Internal Parts, Spring Guides - Evike.com Airsoft Superstore
ICS Pistonhead Ball Bearing for Airsoft AEG Piston Heads, Accessories & Parts, Internal Parts, Piston Heads - Evike.com Airsoft Superstore

Are you wanting to use a LiPo battery?

You need to make sure you check the AOE (Angle of Engagement)
 
#14 ·
FedgeSniper said:
Have you found or looked for barrel ratio charts?
Click to expand...
Most cylinder to barrel ratio charts are wrong by a mile (In fact I do not think I have ever seen a correct one). They have been calculated to get the most fps out a of a certain length barrel when using 0.2gm bb's.
So with a full cylinder they often recommend a 450-500mm long inner barrel. That is OK if you are going to play with 0.2gm bb's but in a DMR that fires 500fps, you want to fling out heavy bb's as they will keep their energy for longer and travel further. These heavier bb's need a lot more air to move them and so this put the ratios on the charts completely off.

Like I have said, I myself have not seen a correct chart.

A suggestion is to try a 6.01mm x 200mm barrel(maybe even slightly shorter) and 0.36gm bb's (note: I am not 100% sure on this ratio as I use an elongated cylinder in my DMR and so it is slightly different to a normal M4)
Using a 200mm barrel will mean you need a bigger spring and high torque motor and maybe some torque up gears to get up to 500fps but the results will be better than you have ever seen.

So in reality, long barrels are not great for DMR's.
 
#15 ·
1tonne said:
Most cylinder to barrel ratio charts are wrong by a mile (In fact I do not think I have ever seen a correct one). They have been calculated to get the most fps out a of a certain length barrel when using 0.2gm bb's.
So with a full cylinder they often recommend a 450-500mm long inner barrel. That is OK if you are going to play with 0.2gm bb's but in a DMR that fires 500fps, you want to fling out heavy bb's as they will keep their energy for longer and travel further. These heavier bb's need a lot more air to move them and so this put the ratios on the charts completely off.

Like I have said, I myself have not seen a correct chart.

A suggestion is to try a 6.01mm x 200mm barrel(maybe even slightly shorter) and 0.36gm bb's (note: I am not 100% sure on this ratio as I use an elongated cylinder in my DMR and so it is slightly different to a normal M4)
Using a 200mm barrel will mean you need a bigger spring and high torque motor and maybe some torque up gears to get up to 500fps but the results will be better than you have ever seen.

So in reality, long barrels are not great for DMR's.
Click to expand...
True that! I should have mentioned that it was more for reference than actual truth
 
#16 ·
Aye, like 1tonne says, most of those charts are for a ratio of 2:1. No good for heavy bb's, where you generally want something more like 2.5:1 :tup:

Take your length to give yourself a ratio like that and then go to the desired fps with .2g bb's. When you put your heavy bb's in you'll get some joule creep but it'll make for the most efficient system ;)
 
#20 ·
1tonne said:
Most cylinder to barrel ratio charts are wrong by a mile (In fact I do not think I have ever seen a correct one). They have been calculated to get the most fps out a of a certain length barrel when using 0.2gm bb's.
So with a full cylinder they often recommend a 450-500mm long inner barrel. That is OK if you are going to play with 0.2gm bb's but in a DMR that fires 500fps, you want to fling out heavy bb's as they will keep their energy for longer and travel further. These heavier bb's need a lot more air to move them and so this put the ratios on the charts completely off.

Like I have said, I myself have not seen a correct chart.

A suggestion is to try a 6.01mm x 200mm barrel(maybe even slightly shorter) and 0.36gm bb's (note: I am not 100% sure on this ratio as I use an elongated cylinder in my DMR and so it is slightly different to a normal M4)
Using a 200mm barrel will mean you need a bigger spring and high torque motor and maybe some torque up gears to get up to 500fps but the results will be better than you have ever seen.

So in reality, long barrels are not great for DMR's.
Click to expand...
Second that.

I guess over the years the idea of matching cylinder to barrel volume ratio stucked on. This whole ratio thing would only make sense if our system was a static one. The air volume in the system is constantly changing in relation to the piston position in the cylinder and bb position in the barrel. Heck even the pressure is not constant at any bb position in the barrel. And oh Gas guns are a whole different ball game.

I say first decide the grams u intend to send, then move on to whatever length barrel and spring you want, finally port away at the cylinder your little heart desires. Move the ports furthur forward bit by bit until the velocity starts to drop. You now have an optimized system. Won't do much to accuracy though, well maybe a little, at least not by a mile.
 
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Airsoft_Newb
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