Double Eagle M908B

[Fatboy40]

@JakeF You have to get that grub screw out otherwise you'll never get the muzzle / flash hider off of it, also DE use a little thread lock on it so it's a total bitch to remove it.

 

I got through a few allen / hex keys that just stripped themselves to nothing as the thread lock is blindingly strong. In the end I had to use the smallest one of these...

 

https://www.amazon.co.uk/dp/B09BYJC2K7/?coliid=I1YDF0OCC4P0WM&colid=2BOB15BB0VKA5&psc=1&ref_=lv_ov_lig_dp_it

 

... to remove it (and my Acetech Brighter-C fitted perfectly).

[RostokMcSpoons]

I ran two Turnigy nano cell 11.1v 1200 mah lipos through the day today.  Rate of fire was noticeably better but the gearbox was whining a bit at the end... Not sure if that is normal after running through several thousand BB's, I'll have to find a video of 'shimming, before and after' to judge.

 

Plenty of kills at range even though my gun chrono'd at a slightly disappointing 270fps with 0.20g but hopped for 0.28g BB's.  If the spring has weakened already then the extra juice might be over stressing things...?

Edited December 5, 2021 by RostokMcSpoons

[Ebeneezer Goode]

Wouldn't worry at fps with hop added, one of the effects is a reduction in velocity and I'd say that 270 with hop applied is decent.

 

Gearbox might just need some lubrication?

 

Springs need time to settle when new, wouldn't worry too much.

[JakeF]

17 hours ago, Fatboy40 said:

@JakeF You have to get that grub screw out otherwise you'll never get the muzzle / flash hider off of it, also DE use a little thread lock on it so it's a total bitch to remove it.

 

I got through a few allen / hex keys that just stripped themselves to nothing as the thread lock is blindingly strong. In the end I had to use the smallest one of these...

 

https://www.amazon.co.uk/dp/B09BYJC2K7/?coliid=I1YDF0OCC4P0WM&colid=2BOB15BB0VKA5&psc=1&ref_=lv_ov_lig_dp_it

 

... to remove it (and my Acetech Brighter-C fitted perfectly).

Thanks for the reply but my problem is actually accessing the grub screw as the rail system covers it so that needs to come off to be able to access it but i havent a clue how to get it off.

[RostokMcSpoons]

On my 906C there's a small hex bolt on a thread that you can see through a slot in underside of the handguard, close to the receiver.  I think you just loosen that off to detach the handguard from the top receiver.
And there's a small hex bolt at the front end of the handguard that also needs undoing.

 

I've not had to take my handguard off, so maybe I've missed something!   Also - I can access the grub screw without doing that (which is nice) - I'll be needing to do that as I've got a suppressor on the way.

 

Edit...

 

Pic of the two things I'm talking about...


Well wouldn't you believe it.  The suppressor I was talking about is a Novritsch one that I ordered on Black Friday... but a little before that I'd ordered a cheapo one from AliExpress, and it's just turned up!   So I had good reason to take the flash hider off mine.  

I had no problem with the grub screw, and no problem with the flash hider either.   No thread lock goo found in mine.
I fitted the suppressor and managed to chew up some of the thread as it's quite fine and very soft and my first attempt wasn't quite done right... so do take care when fitting your tracer (of course, if it's a reputable make it might only go on 'properly').   And I noticed when trying the flash hider back on my slightly mangled thread that it's (now?) quite loose, so that grub screw is important - don't lose it!

Anyway the result is rather nice, though the finish is a little too shiny, i might rough it up with a brillo pad or some polishing paper.   It'll get replaced anyway when my Novritsch modular one turns up, complete with camo cover for a different look... but not bad for less than a tenner!

 

Edited December 6, 2021 by RostokMcSpoons
stuff and nonsense

[Fatboy40]

On 05/12/2021 at 18:45, RostokMcSpoons said:

Plenty of kills at range even though my gun chrono'd at a slightly disappointing 270fps with 0.20g but hopped for 0.28g BB's...

 

Others might not be worried but that sounds horrendously low to me, that would have to be an immense amount of hop to rob you of around 70 FPS from a stock of around 340 FPS?

 

I use 0.25g, the sweet spot for where I usually play, and with the hop set for this I still get around 335 to 340 on 0.20g when put through the chrono (and I'm going to test this myself again tomorrow morning, as I'm off work, to be 100% certain). I swapped in a Guarder SP100 spring a couple of months ago, the DE original had definitely compressed over around four full Sundays of play, however I'm also coming to the conclusion that the air-seal on DE M90X's is not as good as it could be (spring 2022 mine will need a good service and I think I'll swap in a better cylinder head, piston head and nozzle. 

[RostokMcSpoons]

Thanks @Fatboy40

I've got a cheap chrono come over from China, and I was planning to change the spring eventually.  Given that info I'll do it as soon as the  chrono turns up.

It'll also give me a chance to give the internals a look (though probably not as far as opening the gearbox) and maybe get some silicon grease onto the piston head.

[Ebeneezer Goode]

Due to the way hop works, FPS does drop, often substantially, it is nothing to worry about. Regarding full-auto, anyone chronoing 330-340 on 0.20g with hop applied sounds rather suspiciously hot, chrono is usually done without hop applied and at the correct weight used in order to calculate the energy, which is the most important thing as its what we're limited to (1.3j max as per UK Law, most sites are 1.1/1.2j). Of course if you're DMRing and locked to semi you've got much higher limits.

 

Would be interested what the chrono is reading on 0.25g and without hop, sounds like a hot gun North of 1.3j to me.

 

Reason being, it's not the velocity that'll break your eyepro and blind you, its the energy of the pellet, and as hop can be adjusted during play that's why it's checked with no hop applied, i.e. max. velocity/max. joules...

[Rogerborg]

17 hours ago, Ebeneezer Goode said:

Due to the way hop works, FPS does drop, often substantially

 

Although thanks to airsoft physics and air seal shenanigans, it can also go up.

 

 

17 hours ago, Ebeneezer Goode said:

chrono is usually done without hop applied

 

Site dependent, I've never once been asked to dial my hop off.  Some guns need to be disassembled in order to do it.

 

I agree that the legal limit is a hard 1.3J, but it's quite tricky to determine what our gnus are really capable of, given that "any missile" could mean a 0.86g steel BB that would shred the hop and barrel in short order (but the intent is to limit what they could do, not what we would do with them).

 

For all that I'm hot for chrono, I've never been a fan of dialling off to hop.  For safety considerations (as opposed to legality), I'd advocate chronoing in game with the hop and the BB mass that players are actually using, since that's... well, what they're actually using.

 

 

On 05/12/2021 at 18:45, RostokMcSpoons said:

Plenty of kills at range even though my gun chrono'd at a slightly disappointing 270fps with 0.20g but hopped for 0.28g BB

 

Urgh, that's weaker than a politician's excuse.  0.67J, even TM fanbois would have a hard time justifying that.

 

Have you spooged any silicone up the nozzle?  That might be enough to get a better seal. If not, I'd bite the BB and change that spring for a known quantity.

 

[RostokMcSpoons]

1 hour ago, Rogerborg said:

Urgh, that's weaker than a politician's excuse.  0.67J, even TM fanbois would have a hard time justifying that.

 

Have you spooged any silicone up the nozzle?  That might be enough to get a better seal. If not, I'd bite the BB and change that spring for a known quantity.

 

 

I'm still waiting on my chrono to turn up, but it's in the UK so shouldn't be long.  Then I'll be able to show some 'before' figures.  see what it's like with 0.20s and no hop, and with 0.28's both hopped and not.
I'll order an M100 spring now, so hopefully I can swap it over in short order and get some 'after' figures quickly too.

 

Honestly the only time I actively felt out-ranged by a non-sniper on Sunday was when I was up against one of the two HPA players.  Hey, maybe my tactical movement and fieldcraft is so brilliant I got so close I didn't need range   
I'd had plenty of time on the range to get my hop nicely dialled in before play... I was getting the most out of what it had to give.  I was hitting the small metal "40m" sign quite easily, I guess I kept my engagements to that sort of distance.

(Which reminds me, you may remember me talking about one of my first games where I used my old M16 and the tech found it wasn't applying any hop..?  I got some 'disbelief' when I said I was getting ranged kills with that.   Turns out it was shooting rather hot - I'd missed the chronoing session as I'd arrived late and with my kit in a shambles... so it was running quite a bit above the AEG limit. 😳 Luckily (for the poor buggers I was hitting) it was misfeeding on full auto so I was only using it on semi anyway.)

 

edit:  While I'm ordering stuff... any recommendation on the hop rubber and nub?  As the current setup is lifting 0.30s ok, then it's not strictly necessary... but I'm paying a few quid postage so might as well make it all worthwhile

Edited December 7, 2021 by RostokMcSpoons

[Fatboy40]

2 hours ago, RostokMcSpoons said:

edit:  While I'm ordering stuff... any recommendation on the hop rubber and nub?  As the current setup is lifting 0.30s ok, then it's not strictly necessary... but I'm paying a few quid postage so might as well make it all worthwhile

 

A Maple Leaf Macaron 60 Degree and Omega nub are playing nicely in my stock DE M904E hop unit 👍

[RostokMcSpoons]

Ok, next thing is my rate of fire does feel really chuggy when I'm dry-firing it.   
I'm comparing it to my CA M16 which quite frankly sounds like it's got a mad RoF on a LiPo since m'Tech did his servicing on it, but my TM AK47 (also serviced) is noticeably faster too.  

Maybe Jake and I are both being afflicted by the same problem, though mine has take a bit longer to become noticeably poor.

 

If the whole thing was under-lubed to start with and has dried out after a few games that might be an issue...?  Or is that a bit of a reach?
Or is it another sign of a weak spring?  To be honest I'd have thought weak spring = higher RoF, not lower, but I'm willing to hear opinions.
Could the motor need raising / lowering?

A worst case scenario popped into my head - could my gears have lost some teeth?

 

Edited December 7, 2021 by RostokMcSpoons

[Tactical Pith Helmet]

May not even be the rif.  A shit balance charger can charge your batteries to all sort of random states of charge.  Are you testing them on the same battery?

[RostokMcSpoons]

Yes, all on the Titan 7.4v Li-Ion. 

[Ebeneezer Goode]

Yeah, if its labouring might be the battery. Also check motor connection.

 

If you'd lost teeth in the gearbox I'd imagine there would be other noises and weirdness so dont think that would be it...

[RostokMcSpoons]

I haven't done any of my famously wonderful soldering on the M906, so I don't think the connection to the battery is a problem.  The battery is working fine with the other guns.  I could retry one of my other Li-Po's but they're at storage charge levels at the moment.

 

The gun does sound a noisier than the other guns - perhaps it needs some shimming.  Opening up the gearbox is not something I really want to try because I'll probably end up with a bunch of parts and insufficient skills to put them back together properly (as happened with my AK)
 

I will make a slight adjustment to the motor height from the pistol grip baseplate, see if that changes anything, as that's a simple thing to try!

[RostokMcSpoons]

Ok, as it's lunchtime I've picked up my guns and connected the batteries in, and I have to say the DE doesn't sound nearly as sluggish as before.   Maybe it was just too damned cold from a day's skirmishing, and hadn't fully warmed up when I test dry-fired it in the house.

I've made videos of the DE running on both the fully-charged Titan 7.4v Li-Ion, and the probably-almost-empty Turnigy 11.1v Li-Po
See what you think...

 

https://www.youtube.com/watch?v=3-xsDy7hO-M 

https://www.youtube.com/watch?v=vssqdmNKVIA

 

(Not much difference in the RoF between the two batteries to my ear, that 11.1v needs a full charge and I'll maybe re-upload it)

 

and for comparison my Classic Army M16 (which might have been upgraded a gazillion years ago)
https://www.youtube.com/watch?v=wpU5RuvkxeA

 

Edited December 8, 2021 by RostokMcSpoons

[JakeF]

On 06/12/2021 at 10:46, RostokMcSpoons said:

On my 906C there's a small hex bolt on a thread that you can see through a slot in underside of the handguard, close to the receiver.  I think you just loosen that off to detach the handguard from the top receiver.
And there's a small hex bolt at the front end of the handguard that also needs undoing.

 

I've not had to take my handguard off, so maybe I've missed something!   Also - I can access the grub screw without doing that (which is nice) - I'll be needing to do that as I've got a suppressor on the way.

 

Edit...

 

Pic of the two things I'm talking about...


Well wouldn't you believe it.  The suppressor I was talking about is a Novritsch one that I ordered on Black Friday... but a little before that I'd ordered a cheapo one from AliExpress, and it's just turned up!   So I had good reason to take the flash hider off mine.  

I had no problem with the grub screw, and no problem with the flash hider either.   No thread lock goo found in mine.
I fitted the suppressor and managed to chew up some of the thread as it's quite fine and very soft and my first attempt wasn't quite done right... so do take care when fitting your tracer (of course, if it's a reputable make it might only go on 'properly').   And I noticed when trying the flash hider back on my slightly mangled thread that it's (now?) quite loose, so that grub screw is important - don't lose it!

Anyway the result is rather nice, though the finish is a little too shiny, i might rough it up with a brillo pad or some polishing paper.   It'll get replaced anyway when my Novritsch modular one turns up, complete with camo cover for a different look... but not bad for less than a tenner!

 

Yeah mine has both the screws you are talking about so will try that did see them but i hadnt a clue what they where so thought lets not mess with it 30 mins before the games started haha.

On 07/12/2021 at 19:36, RostokMcSpoons said:

Ok, next thing is my rate of fire does feel really chuggy when I'm dry-firing it.   
I'm comparing it to my CA M16 which quite frankly sounds like it's got a mad RoF on a LiPo since m'Tech did his servicing on it, but my TM AK47 (also serviced) is noticeably faster too.  

Maybe Jake and I are both being afflicted by the same problem, though mine has take a bit longer to become noticeably poor.

 

If the whole thing was under-lubed to start with and has dried out after a few games that might be an issue...?  Or is that a bit of a reach?
Or is it another sign of a weak spring?  To be honest I'd have thought weak spring = higher RoF, not lower, but I'm willing to hear opinions.
Could the motor need raising / lowering?

A worst case scenario popped into my head - could my gears have lost some teeth?

 

After some reflection i personally dont think my ROF is that bad as i am only using a 7.4v when the recomended is a 11.1 so that will be one reason. Also have been watching a few speedy boi videos and there HPA ROF is just a different level anyway so comparing it to them is going to make it look like a massive difference.

[RostokMcSpoons]

24 minutes ago, JakeF said:

After some reflection i personally dont think my ROF is that bad as i am only using a 7.4v when the recomended is a 11.1 so that will be one reason. Also have been watching a few speedy boi videos and there HPA ROF is just a different level anyway so comparing it to them is going to make it look like a massive difference.

 

Did you watch my videos? How's yours compare to mine?

 

HPA is ridonculousness, can't compare with that!
 

[ak2m4]

@RostokMcSpoons just watched your video's, I would have expected a bigger jump from 7.4 to 11.1.  Of course a lot of other factors at play.  Ideally it's worth testing with another motor you have have the running in another RIF and compare the 2.   Still the original motor?  I imagine the stock motor is super bargain basement.  

[JakeF]

27 minutes ago, RostokMcSpoons said:

 

Did you watch my videos? How's yours compare to mine?

 

HPA is ridonculousness, can't compare with that!
 

not yet as im in work and cant access youtube but will have a look on my lunch and get back to you.

[RostokMcSpoons]

16 minutes ago, ak2m4 said:

@RostokMcSpoons just watched your video's, I would have expected a bigger jump from 7.4 to 11.1.  Of course a lot of other factors at play.  Ideally it's worth testing with another motor you have have the running in another RIF and compare the 2.   Still the original motor?  I imagine the stock motor is super bargain basement.  

Do please bear in mind that the 11.1v is right down near storage-level charge... ~10.5v total, ~3.50v per cell
I suspect that'll be the real reason...?
I'm bunging one on charge now, I'll re-test and re-upload at lunch.

[JakeF]

5 minutes ago, RostokMcSpoons said:

Do please bear in mind that the 11.1v is right down near storage-level charge... ~10.5v total, ~3.50v per cell
I suspect that'll be the real reason...?
I'm bunging one on charge now, I'll re-test and re-upload at lunch.

Yeah the charged one shoulkd 100% make a difference like never know motor might be topped out but more likely the charge of the battery. let me know when you have uploaded again im keen to see the difference.

[RostokMcSpoons]

Oh bejeezus... I've been charging my Li-Po with the selector switch set to Li-Fe.   Have I buggered it?

[JakeF]

25 minutes ago, RostokMcSpoons said:

Oh bejeezus... I've been charging my Li-Po with the selector switch set to Li-Fe.   Have I buggered it?

if it hasnt blown up it should be fine i'd give it a proper balance charge just to be safe and then it should be back to normal