DE M908a Spring Change for better FPS

[Stillers80]

Hi all. 
 

I’m looking to bump up the joules/FPS on my M908a, essentially hoping to run DMR type system. Does anyone have a recommendation for a spring to use to get me up nearer to 400fps? I’m currently sitting around 280fps.

Cheers

 

[Krisz]

Too many factors to consider so it's impossible to tell. Good airseal and a quality inner barrel can make a huge difference.

Also, you need a rough idea regarding BB weight otherwise you are gonna end up joule creeping and they are not gonna let you to use your gun.

I looked up a spring chart on ak24m and I decided to run 0.36 so I bought few different ones between M110-M140 for now. On one site your gun is perfectly fine and you go somewhere else and it's too hot on the same spring/same BB. That's why you need to able to lower your FPS. Real quick change spring system isn't that bad regarding this issue. You need a stronger motor to pull a  stronger spring just keep in mind.

For me an electric DMR is always a heavy stress build so it's not a bad idea to radius your GB and correct your AoE. 

 

[RostokMcSpoons]

Is that 280fps with 0.20's?    You may just have suffered the Double Eagle Cheese Spring issue.   Trying slapping in a new M100 or M105 spring, and also put in a new hop rubber. That should get you back to 340-350fps, and able to lift 0.32's to a decent range.  You might be happy enough with that before trying the full DMR approach, with the problems that brings (i.e sites that need a hardware change for semi-auto, rather than just programming the gun...  the MED range issue... etc etc)

 

[Krisz]

Is that 280fps with 0.20's?    You may just have suffered the Double Eagle Cheese Spring issue.   Trying slapping in a new M100 or M105 spring, and also put in a new hop rubber. That should get you back to 340-350fps, and able to lift 0.32's to a decent range.  You might be happy enough with that before trying the full DMR approach, with the problems that brings (i.e sites that need a hardware change for semi-auto, rather than just programming the gun...  the MED range issue... etc etc)

DMR has to be physically locked to semi? Real headache.

I was so happy to buy my DE coz I can program it to safe-semi-semi.

 

[RostokMcSpoons]

DMR has to be physically locked to semi? Real headache.

I was so happy buy my DE coz I can program it to safe-semi-semi.

Yeah it kind of sucks, but you can appreciate there are too many people out there who'd abuse an honour system with that. 

Plus the small matter that a gun that can shoot full auto at higher velocities is actually illegal...

You might get away with just drilling and tapping a hole in the receiver and screwing a bolt into it, to physically prevent selecting full auto.  I'd check with your site though.  Even that's a bit too easy to reverse on the field.   I'll let more knowledgeable people tell you how to do a permanent alteration (that can still be reversed by replacing one component, though it'll involve opening the gearbox)

If the site limit is 400fps, you have to question whether losing full auto and the ability to engage at < 20/30m is worth giving up for that small extra velocity (which might only give you an extra 5 or 10m range)

You made a good purchase, though, I love my DE ?

 

[Krisz]

Yeah it kind of sucks, but you can appreciate there are too many people out there who'd abuse an honour system with that. 

Plus the small matter that a gun that can shoot full auto at higher velocities is actually illegal...

You might get away with just drilling and tapping a hole in the receiver and screwing a bolt into it, to physically prevent selecting full auto.  I'd check with your site though.  Even that's a bit too easy to reverse on the field.   I'll let more knowledgeable people tell you how to do a permanent alteration (that can still be reversed by replacing one component, though it'll involve opening the gearbox)

If the site limit is 400fps, you have to question whether losing full auto and the ability to engage at < 20/30m is worth giving up for that small extra velocity (which might only give you an extra 5 or 10m range)

You made a good purchase, though, I love my DE ?

I don't want to open my gb straight away. Just having bit of fun changing minimal amount of internals and have a feel for it before either jumping into a kythera or wolverine mtw. Rather spending 100 pounds on BB and parts and finding out okay this isn't for me than spending big boy money on stuff I won't enjoy.

I think the whole dmr thing is only viable when you can outrange your opponent. Otherwise what's the point?

Personally I'm not bothered about auto in general I played so much on semi indoor I use semi outdoor, too. 

 

[RostokMcSpoons]

I don't want to open my gb straight away. Just having bit of fun changing minimal amount of internals and have a feel for it

.. Is absolutely the best way to go    I've 'done things' to a couple of my guns in an attempt to improve them, which really didn't - and I now regret (... a bit... at least I learned from the experience)

 

[Lozart]

DMR has to be physically locked to semi? Real headache.

I was so happy buy my DE coz I can program it to safe-semi-semi.

Depends on the site. Read Alert are happy with electronic Semi only.

 

[Stillers80]

Too many factors to consider so it's impossible to tell. Good airseal and a quality inner barrel can make a huge difference.

Also, you need a rough idea regarding BB weight otherwise you are gonna end up joule creeping and they are not gonna let you to use your gun.

I looked up a spring chart on ak24m and I decided to run 0.36 so I bought few different ones between M110-M140 for now. On one site your gun is perfectly fine and you go somewhere else and it's too hot on the same spring/same BB. That's why you need to able to lower your FPS. Real quick change spring system isn't that bad regarding this issue. You need a stronger motor to pull a  stronger spring just keep in mind.

For me an electric DMR is always a heavy stress build so it's not a bad idea to radius your GB and correct your AoE. 

Thanks for replying! Yeah, I think there are some small adjustments I can make regarding air seal etc. I’ve been running .25g but have been thinking of upping to .28g for better accuracy without compromising too much on distance.

I think having the quick change spring system will allow me to experiment a bit more confidently. I also don’t to be opening up the GB as a newbie and getting things wrong. Though I do like to learn how to do things myself ?

Is that 280fps with 0.20's?    You may just have suffered the Double Eagle Cheese Spring issue.   Trying slapping in a new M100 or M105 spring, and also put in a new hop rubber. That should get you back to 340-350fps, and able to lift 0.32's to a decent range.  You might be happy enough with that before trying the full DMR approach, with the problems that brings (i.e sites that need a hardware change for semi-auto, rather than just programming the gun...  the MED range issue... etc etc)

Thanks for replying!

280fps with .25g. It’s a new gun so perhaps I’ll just fit a new spring and see about getting to around 350fps before I make a decision to go down the DMR route. Or, perhaps I just look at running a dedicated DMR gun and spend some more cash ?

I’m loving the gun so far though, especially after using hire guns for a while. Being able to hit a half decent range makes all the difference. 

 

[RostokMcSpoons]

280fps with .25g. It’s a new gun so perhaps I’ll just fit a new spring and see about getting to around 350fps before I make a decision to go down the DMR route. Or, perhaps I just look at running a dedicated DMR gun and spend some more cash ?

I’m loving the gun so far though, especially after using hire guns for a while. Being able to hit a half decent range makes all the difference. 

I can't remember what my gun was shooting at when new, but looking at a joule chart, you should be able to push to 313fps with 0.25's, although the hop setting makes a big difference.  Still, there's probably some headroom for a better spring.    And if you're doing the spring, you might as well change the hop rubber too... something a little softer than the stock one.   I went for the good ol' Maple Leaf Macaron 50 Degree + Omega nub combo.   You might just want to pick a G&G Green or Guarder Clear and stick with the existing nub.   Seek opinions on that

I've used 0.28s in my DE for a while now - very happy with those, until Windy Saturday (just gone) showed me that 0.32s are even better.  They are noticeably pricier too, of course, but what's a few quid extra spread over 3000 shots, and given the overall cost of the day.

 

[Krisz]

Thanks for replying! Yeah, I think there are some small adjustments I can make regarding air seal etc. I’ve been running .25g but have been thinking of upping to .28g for better accuracy without compromising too much on distance.

I think having the quick change spring system will allow me to experiment a bit more confidently. I also don’t to be opening up the GB as a newbie and getting things wrong. Though I do like to learn how to do things myself ?

Thanks for replying!

280fps with .25g. It’s a new gun so perhaps I’ll just fit a new spring and see about getting to around 350fps before I make a decision to go down the DMR route. Or, perhaps I just look at running a dedicated DMR gun and spend some more cash ?

I’m loving the gun so far though, especially after using hire guns for a while. Being able to hit a half decent range makes all the difference. 

Well you can change hop-up rubber, nub, inner barrel and hop-up unit and not opening up your GB. Compression is different. 

If it's your first gun or a back-up gun I wouldn't touch internals because it's just shit when you can't play because your gun in pieces at home (don't ask me how I know it ). Just buy a cheapo m4 take it apart until the last screw and that will give you enough confidence regarding V2 gearboxes.

 

[Cannonfodder]

I’ve been running .25g but have been thinking of upping to .28g for better accuracy without compromising too much on distance.

You might find that the heavier ammo gives better range without needing to swap out parts. I found this was the case for both my galaxy MP5K and cyma M4. If you're switching to heavier ammo anyway then this could save you some cash

 

[Fatboy40]

@Stillers80 I run my M908A as a DMR, with an M130 spring shooting 0.40g BB's.

I'll read through this thread but feel free to bombard me with questions if I can help at all

Edit: This is pretty much how it looks at the moment...

https://i.imgur.com/z0AVJpA.jpg

... but with the metal receiver being a lot more worn plus a an IMI Defense vertical grip on the handguard.

Edit 2: Be careful about what you expect you'll be getting regarding a DMR from just a spring change, as to get a genuinely effective DMR you have to go way beyond that.

For example, off the top of my head, these are what have been swapped into my M908A (lots of parts from AK2M4)...

- 410mm Maple Leaf (aka ML) AEG inner barrel.
- ML 70 degree MR bucking.
- ML Omega nub.
- ZCI rotary hop unit (the stock hop unit has a pants arm).
- Maxx Model 21.25mm nozzle.
- Maxx Model cylinder head.
(However, I'd personally say that the "XT M4 CYLINDER HEAD ALUMINIUM (PAD)" is as good if not better)
- ZCI 4/5 cylinder.
- XT 14 tooth CNC rack piston.
- GearParts / XT M130 spring. 
- XT 22 TPA high torque motor.

... at some point I'll buy a Maxx Model M4A-PRO hop unit for it, like I have in my DE M904E, as they're just so good and the solid metal nub work perfectly with the ML MR bucking (don't buy a Retro Arms CNC hop unit as they don't fit in the DE M900's, plus the finishing on two I bought were poor with noticeable burrs).

 

[Fatboy40]

I was so happy buy my DE coz I can program it to safe-semi-semi.

Everywhere I play would not let you use it as a DMR under those circumstances, it has to be a mechanical and not software lock.

 

[Krisz]

Everywhere I play would not let you use it as a DMR under those circumstances, it has to be a mechanical and not software lock.

Yes it's totally dependant. I asked Warzone Coventry yesterday they said as long I don't abuse it and program it back to able to shoot full auto and it's checked regurarly and chronod they have no problems with electronically programmed DMR's.

 

[Stillers80]

@Stillers80 I run my M908A as a DMR, with an M130 spring shooting 0.40g BB's.

I'll read through this thread but feel free to bombard me with questions if I can help at all

Edit: This is pretty much how it looks at the moment...

https://i.imgur.com/z0AVJpA.jpg

... but with the metal receiver being a lot more worn plus a an IMI Defense vertical grip on the handguard.

Edit 2: Be careful about what you expect you'll be getting regarding a DMR from just a spring change, as to get a genuinely effective DMR you have to go way beyond that.

For example, off the top of my head, these are what have been swapped into my M908A (lots of parts from AK2M4)...

- 410mm Maple Leaf (aka ML) AEG inner barrel.
- ML 70 degree MR bucking.
- ML Omega nub.
- ZCI rotary hop unit (the stock hop unit has a pants arm).
- Maxx Model 21.25mm nozzle.
- Maxx Model cylinder head.
(However, I'd personally say that the "XT M4 CYLINDER HEAD ALUMINIUM (PAD)" is as good if not better)
- ZCI 4/5 cylinder.
- XT 14 tooth CNC rack piston.
- GearParts / XT M130 spring. 
- XT 22 TPA high torque motor.

... at some point I'll buy a Maxx Model M4A-PRO hop unit for it, like I have in my DE M904E, as they're just so good and the solid metal nub work perfectly with the ML MR bucking (don't buy a Retro Arms CNC hop unit as they don't fit in the DE M900's, plus the finishing on two I bought were poor with noticeable burrs).

Thanks for a detailed reply, that’s awesome.

At the moment I think I’m just going to upgrade the spring, hop rubber (if you have a recommendation, great) and inner barrel. I love the idea at the moment of running a DMR but don’t want to be be restricted by it. I think buying a dedicated gun for it is going to be a better way to go.

Yes it's totally dependant. I asked Warzone Coventry yesterday they said as long I don't abuse it and program it back to able to shoot full auto and it's checked regurarly and chronod they have no problems with electronically programmed DMR's.

We’re looking at coming to Wazone Cov soon, as our closest site (Comms Site 3) has closed because of HS2 works ?

 

[RostokMcSpoons]

I can personally recommend the Macaron 50 deg + Omega combo.  The 50 is quite soft which means it can give more spin, but eventually it'll get chewed up and need replacing.  A simple job.  Hop rubbers are considered a 'consumable'.
The 70 degree one in @Fatboy40's specification is a bit stiffer, and therefore more resilient when under the extra pressures his DMR will run at.

Always a good idea to try here first...   

https://www.ak2m4.co.uk/internal-parts/hop-up-buckings-nubs

because @ak2m4 is here on the forums and he's beyond helpful with any tech questions you might have

I've got an ASG M105 spring in mine... different makes will give different results for the same rating so you might have to buy a couple before you hit the ideal power level.  But hey they're cheap enough, and the quick change system makes them relatively painless to fit.  If one is slightly too powerful and you can't be arsed to source a less powerful one, then you can always start cutting coils off the end (I've never had to as yet).   Again, ak2m4 might be able to help with his experience.
https://www.ak2m4.co.uk/internal-parts/springs
 

ZCI barrels have a good rep, plenty here...
https://www.ak2m4.co.uk/internal-parts/inner-barrels
I've not got around to changing barrel on mine, I had a poor experience when I first 'upgraded' my TM AK47 with a tight bore, and then had no-end of jams with BBs failing to get through properly.  I think that was more down to the poor state of the cheap ammo that I used back then, they're probably fine now... but my DE runs accurately with the stock barrel.  One day I'll try a replacement - more accuracy is always welcomed!

One more item to consider is the motor.  The standard grey motor in the DE's is quite cheap and not the best.  It can get a bit toasty under heavy load, so this 
https://www.ak2m4.co.uk/shs-high-torque-motor-16tpa-long

is a recommended (but not essential!) upgrade... just a straight swap for the existing motor.  

 

[Stillers80]

I can personally recommend the Macaron 50 deg + Omega combo.  The 50 is quite soft which means it can give more spin, but eventually it'll get chewed up and need replacing.  A simple job.  Hop rubbers are considered a 'consumable'.
The 70 degree one in @Fatboy40's specification is a bit stiffer, and therefore more resilient when under the extra pressures his DMR will run at.

Always a good idea to try here first...   

https://www.ak2m4.co.uk/internal-parts/hop-up-buckings-nubs

because @ak2m4 is here on the forums and he's beyond helpful with any tech questions you might have

I've got an ASG M105 spring in mine... different makes will give different results for the same rating so you might have to buy a couple before you hit the ideal power level.  But hey they're cheap enough, and the quick change system makes them relatively painless to fit.  If one is slightly too powerful and you can't be arsed to source a less powerful one, then you can always start cutting coils off the end (I've never had to as yet).   Again, ak2m4 might be able to help with his experience.
https://www.ak2m4.co.uk/internal-parts/springs
 

ZCI barrels have a good rep, plenty here...
https://www.ak2m4.co.uk/internal-parts/inner-barrels
I've not got around to changing barrel on mine, I had a poor experience when I first 'upgraded' my TM AK47 with a tight bore, and then had no-end of jams with BBs failing to get through properly.  I think that was more down to the poor state of the cheap ammo that I used back then, they're probably fine now... but my DE runs accurately with the stock barrel.  One day I'll try a replacement - more accuracy is always welcomed!

One more item to consider is the motor.  The standard grey motor in the DE's is quite cheap and not the best.  It can get a bit toasty under heavy load, so this 
https://www.ak2m4.co.uk/shs-high-torque-motor-16tpa-long

is a recommended (but not essential!) upgrade... just a straight swap for the existing motor.  

That’s awesome, cheers for that. Gives me some light reading for the evening going through the ak2M4 site!

 

[Fatboy40]

Thanks for a detailed reply, that’s awesome.

At the moment I think I’m just going to upgrade the spring, hop rubber (if you have a recommendation, great) and inner barrel. I love the idea at the moment of running a DMR but don’t want to be be restricted by it. I think buying a dedicated gun for it is going to be a better way to go.

With time, effort and money you can tweak / get a standard 1.14 Joule AEG to shoot quite far if using a decent BB weight like 0.32g, certainly to the point where you can stand 10 meters further away than other players on your teams and shoot the exact opposition that they're engaging and know that most of the opposition players BB's will fall short and not get you. If you go on YouTube "Negative Airsoft" is spot on when he says in one video from 2023 that you can build an all purpose battle rifle that can be used for CQB and then the next moment be used as a half way house to a DMR when outside (it's what my M904E is now).

I do enjoy having my DMR though, especially as I'm 50 / not that fit, and I'll play the morning with it then swap to my M904E after lunch. The major downside of running a DMR though is that you MUST have a sidearm as you'll only be able to shoot at people if they're over a certain distance away from you (MED, aka "Minimum Engagement Distance"). So, once say an enemy gets closer than 15 meters to you you'll need to use your sidearm / pistol to shoot them as getting hit close range with a heavy BB bloody hurts and will draw blood even through clothing. My sidearm is a mildly upgraded AAP-01.

Others have recommended parts from AK2M4, and this parts supplier is damned good and is happy to answer questions, so if as your post all you want is to shoot at around 400 FPS on 0.20g BB's with your M908A then I've a feeling that a GearParts / XT M120 spring will be the safest option for you (possibly an M130, but if one day you're building a DMR I'd buy both anyhow as they're so cheap). This will give you the raw power, but your air volume etc. will not be high enough, so don't expect to become a lethal killer on the field

Also the inner barrel you have is good enough, you don't really need to replace it, but I did with mine as I took it to the next level and wanted a Maple Leaf inner barrel to get a 100% perfect fit with the ML MR bucking (which with the right nub is a simple to install R-Hop).