[mike0brien]

I'm sure it's been asked before... but where did you get the material for the brass shims? I tried tin foil but it is really flimsy. I was considerig finding my old feeler gauge and cutting that up but id rather not butcher a good tool.

 

[DeKamme]

So good to see that research, real-world testing and knowledge have let such an old guide stay alive for this long. And good to see the OP already stated that barrel length/tightbore increasing accuracy is a myth years ago.

I'm going to use quite some bits, the floss-tip seems like a very good alternative to smearing odd pastes or wrapping teflon, especially when you need to go back to correct something.

Since most fields here are limited to 350FPS, except for bolt actions, a true longer range DMR won't be possible. In stead I'm going for consistency and accuracy in my AEG. I seldom use full auto and love fieldcraft, so it frustrates me greatly to see a first shot or follow-up shot divert greatly on the horizontal axis, and get spotted due to sound or the angle of impact.

So besides air seal, I should focus on the hop chamber/bucking for consistency and accuracy. I'm wondering what opinions are on recent hop hacks compared to the flush bucking in this guide. I'd rather cut open and cobble together my own contraptions than spend premium cash on a small piece of rubber.

I'm particularily interested in r-hop. In my opinion the hack mentioned here stretches the bucking far more then intended, causing a lot more wear, and thus inconsistent results over extended periods (that are probably solvable by hop dial readjustment).
While the r-hop with more contact area and more evenly spread contact should lessen wear and improve consistency.

This is all my opinion, I have not used the hop type in this guide, and would like to hear if someone has more insight in the matter. If so, please elaborate on the 'nub' or it's alternative you used?


Also, are there parts in this guide that have been considered obsolete, because of more efficient/more easy ways to reach the same results? Or should I see this as a starting point, and continue with topics like teflon mods or inner barrel locks separately? I see a lot of differing opinions on the matter and am having a hard time picking which way to go.

 

[Lokker]

Long text

About the hopup - some rubbers just plainly fit - no need for any floss mod. I use anaerobic gasket maker to seal the hopup rubber on my DMR, you can remove it easily as well (at least the one I use). As you have a 350fps limit, you definitely should look into R-hop, there are easier methods than the old sandpaper method today. You can get cheaper patches on Ebay. R-hop will allow you to get a consistent hopup applied to heavier BBs without upping the FPS. The nub isn't that big of a deal if you install it correctly, but you can also use an eraser and shape it into a M-nub.

Also hopup rubbers are a jungle! Some have small lips, too short lips, to thick, you don't always need to sand down the tappet plate as this can mess with your BB feeding. Also stretching O-ring is in my opinion temporary - Buy a new O-ring instead. Same with Nozzles - The best I've found is to simply use CA and glue a small O-ring with a tight fit onto the nozzle.

I'd also work on making the gun more quiet - Hammar mod helps and it will also help with consistency. Imo it's better than sorbo because it makes use of the lost space with sorbos, thus not losing fps. Volume balancing also helps. Suppressors with foam helps but I think they're illegal in the US so an alternative could be to remove the muzzle brake.

 

[jphaney]

SR 25 and EAGs

I tried to access the sights for there information. received error message ( no longer available ) Could you repost these items please?

 

[hakkifin]

Hello!

I have been building a DMR out of my A&K SR-25, but I've came across a few issues. FPS loss and the wiring keeps heating up really badly (but the motor & battery stay cool).

Internally:

-Airsoft pro original ratio gears
-SHS type 0 cylinder
-SHS M4 cylinder head
-SHS 19teeth piston & SHS piston head
-Lonex AUG nozzle
-ACM spring guide
-SHS high torque motor
-M130 - M140 spring

This setup gives me less than 130m/s with 0,20g BB's. The cylinder is sealed 100% so that leaves me with a leaking nozzle / hop up. I'm still with the A&K original hop up chamber and barrel. Tried different buckings to see if the nozzle would fit them better, but so far no results. Is there any other nozzles (lenght wise) that I could try?

Then the heating issue. Shimming is pretty much as good as it gets, but could my original bearings or the original (rather thin) wiring be the issue?

 

[BoesBoes]

G36 nozzle works too or you could buy the custom unit7 nozzle from airsoft pro. Easy pic'n chart
The stock hop chamber might be your problem here though.

As for the wiring idk guess you could try thicker wires.

 

[Twistedc]

Sorry for not reading every page, but just at work thinking about things to do to my gun...but is there anyway to get the original pics back up on the first post. I know its over 5 years old though

Also got a tad lost on the one part, but will just reread it atter work today..awesome work and thanks for putting in the effort

 

[ahp]

Sorry for not reading every page, but just at work thinking about things to do to my gun...but is there anyway to get the original pics back up on the first post. I know its over 5 years old though

Also got a tad lost on the one part, but will just reread it atter work today..awesome work and thanks for putting in the effort

Sorry bud.
Looks like Vin was using photobucket to host the images and they are no longer in the same link Vin was using.

 

[Twistedc]

Thats ok, i figured so..i think i may have found a website that copy and pasted it all

 

[Twistedc]

THE Holy Grail of building your DMR AEG - Airsoft Technical Discussion - Oklahoma Airsoft

 

[Plazmaburn]

Fixed most of the images.

 

[TriggerHappy]

Is there any way to prevent the motor brush springs from melting? I've gone through 3 already. Using a matrix magnum high torque and a 9.6 with a mosfet (Lipo in progress)

 

[Five_Seven(57)]

Is there any way to prevent the motor brush springs from melting? I've gone through 3 already. Using a matrix magnum high torque and a 9.6 with a mosfet (Lipo in progress)

Something its wrong there... never heard that and in my team there are players that misuse the guns.

Is it well shimmed? How is the motor height? You have there the real Joule effect...

 

[BoesBoes]

Is there any way to prevent the motor brush springs from melting? I've gone through 3 already. Using a matrix magnum high torque and a 9.6 with a mosfet (Lipo in progress)

What?! The power shouldn't even go thru those springs.. :shrug:
Could you post a picture?

 

[TriggerHappy]

Here ya go..

Ive never worked on a gearbox and have been wanting to turn my CA SA-58 into a dmr
So I ordered
-Guarder ITU m150 kit
-Matrix magnum
-11.1 1600 mah
-Burst Wizard 2
And went through trouble shooting, I made a thread in the Classic Army rifle section
I just ordered bushings since the ones that came with the kit are to small (6mm)

 

[TriggerHappy]

Looking at the positive connector wire,there was a tear in it. It wasn't very noticeable until I messed with it

 

[BoesBoes]

Guess it touched the spring? Just to be sure, are the connector 'clips' from the wires you put on the +/- motor tabs insulated?

 

[STEALTHRABBIT]

I was wondering if you guys could help me finalize my build list before I place my order. I bought this MK12 DMR in non-firing/working order and ive been researching how to build it into a proper DMR for almost a month now and I just found this article now I'm really overwhelmed a bit. So I decided to use the SB 6mm gearbox shell that came with the mk12 and put bushings in it. I've built up a list of what I'll think I need but I just wanted a few opinions from experienced builders before I go ahead and order any parts. I'm looking to build it to 410-450fps using .27 bbs if that mathematically makes sense. I was thinking of getting a M120 spring im just not sure what brand is rrally good. The DMR has a 500mm tight bore barrel. I haven't taken apart the hop up yet as I was told it was flat hop by the previous owner but I bet that will need some freshening up also. Any help is more than appreciated.

Thank you.

 

[Sam]

OK guys may i benefit from your great experience and assist me in my project?
I've been looking for A&K SR25 AEG and upgrade it, which (1tonne and petter2093) help me so much to reach the best result and I am very grateful to both of them.
But after extensive research i got to the fact that the AEG snipers can not relied on.
Therefore I'm going to buy HPA PolarStar Jack system to my SR25 project but at the same time I am facing challenge make me unable to figure out what is the best hop up unit and bucking plus barrel i have to use to make the sniper extremely accurate and consistent!
Because many people who used the HPA system were unable to find the best selection i mentioned already, take for example BrainExploder from youtube he built AEG Barrett .50cal M82 Sniper Rifle HPA but at the end he was facing troubles even withe best of different (hop up unit and bucking, barrel) he put it in the gun. Which caused to curve the bb's to the right and then he put back all the stock (hop op, bucking, barrel) again to shoots straight just like before.
Now in my case if i choose the A&K SR25 no doubt the stock (hop op, bucking, barrel) is the worst in the market. Because what i should to except from gun around $240,-?
If i choose the G&G GR25 i have no idea what (hop op, bucking, barrel) install inside?
So is it worthy to $475,- ~ $500,-?
All together does anybody here built DMR sniper using HPA PolarStar Jack system reached good solution?
Thank you.
BrainExploder video to better understand this issue than i explain it.

Note my desire project:
Semi-Auto only.
450fps

 

[littlej]

If you move to HPA and you look for consistency consider getting a FE engine not a Jack, the later one has an open bold system which is hard to tune correctly and get good results, the FE engine can run closed bolt which for a DMR setup it works wonders. Trust me i went from an open bold to a FE and i don't regret it. Also get a good regulator something like a Redline SFR or how is it called and you can get a bad ass dmr, i also moved from a SR25 AEG to a HPA one but switch to M4 platform since it's easy to find mid caps. Feel free to pm if you need extra help.