Upgrade Suggestions for A&K SR25?

[AG1212]

Its about time I upgrade my long knackered and unused AEG. I have heard very mixed reports on internal compatibility so hopefully you knowledgeable folks can shed some light!

 

I heard that the gearbox is a ver 2 with some unique parts but I also heard these parts are compatible with some ver 4 parts ( psg1 I believe ) but which is it?

 

Also I am shortening the barrel to a 14inch, but I remember hearing that some of the internals are bore up? which ones?

 

The parts I am planing on replacing are the nozzle ( AUG nozzle would suffice? ) bushings ( 7mm? ) piston if possible ( hard to find sr25 specific ) and cylinder head (no clue about compatibility) piston head which I believe is standard ver 2?

 

 

Thanks for the help!

[wolf1]

To my knowledge the parts that are specific to the SR25 long gearboxes are the -

 

Tappet, cylinder, gearbox shell, piston and the gear that interacts with the piston.

 

Not sure why you need an AUG nozzle unless the A&K is different to all the others your after an M4/M16 one.

 

If I was you I would buy or make a spacer for the piston (ones for the SA80 will work as well) then that allows you to drop your preferred brand of gears and piston in.

 

Edit: you should not experience any noticeable "suck back" dropping to a 14" barrel. Bore up kits have thinner cylinder walls and slightly larger diameter piston heads.

[AG1212]

I heard that suck back actually doesn't exist, and that if you use bore up parts with a short barrel you'll damage the internals, IE the bb is pushed out while the piston is only half way and slams the rest of the way, like dry firing.

 

So what parts are bore up if any? ( I want to replace them ) and is the cylinder compatible with the psg1 or not? ( ie what lenght is it )

 

The nozzle isn't a standard ver 2 from what I can tell, and I heard from somewhere that an AUG nozzle would suffice.

 

What do you mean by a spacer for the piston? where is it placed etc?

 

Thanks for the reply.

[mugur]

Suck back does exist, but only on long barrels. Otherwise why PDI would have created their VC line of pistons?

[Banshee_Will]

Quite interesting and has some tips plus the information to back it up.......

 

"THE Holy Grail of building your DMR AEG"

http://airsoftsniper.proboards.com/index.cgi?board=aeg&action=display&thread=1291&page=1

[Docv400]

...What do you mean by a spacer for the piston? where is it placed etc?...

The spacer goes between the piston and the piston head, it basically makes up the length difference between the 19 tooth (SR25) and 16 tooth ('normal' AEG) pistons.

You also need to take 3 teeth off the sector gear, or use a 'standard' AEG one.

 

As wolf1 mentioned, it's the same mod as on the SA80/R85 models.

I've done it to a few of those now, plus a couple of SR25s, either with a spacer, or my preferred method, a custom machined piston head which incorporates the spacer length.

 

The spacer option...

 

Or the extended head method...

 

EDIT: I also incorporate enough length to correct the Angle of Engagement as well, in both the spacers and the heads.

Also, the volume you lose using a 16 tooth piston (due to the shorter stroke) will compensate nicely for the shorter barrel.

 

 

 

[AG1212]

Sorry for the very late reply

 

@Docv400

 

Thanks for the info, do you know where I can get a spacer or bigger piston head? or could you make me one

 

@mugur

 

Why do people buy 6.01 barrels for better accuracy when that in fact is only good for fps gain? If I can find that thread again I will post it but accoring to their calculations and personal experience it is not possible, but that's a whole different topic.

 

@Banshe_Will Cheers for that link M8! that really answered all my questions lol.

[Vice]

 

Why do people buy 6.01 barrels for better accuracy when that in fact is only good for fps gain? If I can find that thread again I will post it but accoring to their calculations and personal experience it is not possible, but that's a whole different topic.

 

 

Because the better made upgrade barrel will be more accurate than the stock barrel. They would probably notice a nice accuracy increase with an upgrade barrel of the same bore as the stock barrel.

 

The 6.01 just has the nice effect of bumping fps up quite a bit alongside the improved accuracy.

[Docv400]

 

Thanks for the info, do you know where I can get a spacer or bigger piston head? or could you make me one

 

PM'd you...

 

 

 

[AG1212]

Because the better made upgrade barrel will be more accurate than the stock barrel. They would probably notice a nice accuracy increase with an upgrade barrel of the same bore as the stock barrel.

 

The 6.01 just has the nice effect of bumping fps up quite a bit alongside the improved accuracy.

 

 

 

But why choose a 6.01 barrel over a 6.04 of the same high quality when the latter is more accurate and the FPS gain is negligible in that FPS isn't everything, especially without accuracy.

 

 

But anyway back on topic.

Seeing as I can use standard pistons if I use a spacer, what would be the best piston for a 1joule setup prob using a 11.1v battery on mostly semi? basically what can withstand the speed. And to add to that what gear set would best accompany it? ( standard ver.2/3 ).

[Docv400]

Standard Marui piston, I use nothing else (unless the customer specifies otherwise) and have never had one fail.

You need to have the Angle of Engagement set correctly of course, otherwise it will wear out too soon, the same as any piston will.

[Vice]

But why choose a 6.01 barrel over a 6.04 of the same high quality when the latter is more accurate and the FPS gain is negligible in that FPS isn't everything, especially without accuracy.

 

 

But anyway back on topic.

Seeing as I can use standard pistons if I use a spacer, what would be the best piston for a 1joule setup prob using a 11.1v battery on mostly semi? basically what can withstand the speed. And to add to that what gear set would best accompany it? ( standard ver.2/3 ).

 

TO the first part: Because most people don't read all the threads on accuracy/FPS vs barrel diameter. I'm not saying 6.01 is better - I was just saying the average airsofter hasn't considered their choice very much and jumps into the 'Tightest barrel am best' camp.

 

The A&K AR25 uses standard v2/3 gears (at least mine does).

 

If i was going to run an 11.1v and use mainly semi I would definitely get/make a MOSFET with breaking (an AB mosfet) to reduce the chance of lockups and to reduce wear on trigger contacts and to improve the response time.

[AG1212]

Yes that was the plan, though the mosfet I'm after isn't available at the mo. The sector gear is not standard as far as I know, unless you change the piston to standard with a new head which is what Im planing to do.

[hessu75]

Hello all,

 

I am also upgrading my A&K SR25 AEG.

 

I bought the rifle defective. It did not have a working trigger mech. Had a mosfet when owned by the previous airsofter.

 

Anyhoo,

 

Dismantled the whole rifle and noticed, that the original piston was in a sorry state. Last few teeth were stripped.

 

So, I made an order from Evike, and ordered the Matrix made all alu CNC machined piston, with steel teeth. Specially made for SR25.

There were some other pistons, with steel teeth. Like the Hornbill made. But, I read some reviews, that tghis piston would not fit the A&K made SR25 and tended to sink the teeth "inside" the piston. Cheap plastic IMO.

 

I have not installed the piston yet.

 

Can anyone shed some light to this piston? How does it perform etc? Tried to find reviews from other sites, but no help there.

 

Also,

 

I have the mecha split up now ATM. I am installing the AB mosfet. Is it overkill to file down/ round up the corners, where the cylinder hits, when operating the rifle?

 

Can someone also tell me what kind of motor is housed inside the A&K SR25. No markings at all? My motor is all blank. Nothing. No stickers. Nothing.

 

Cheers

 

-Hessu-

[jesse100]

i am looking at fitting a tanio koba hop twist barrel to my sr25 as most sites limit fps to 350 and the barrel works best at 300 ish has any one else used one?

[ertgunner]

get a 6.01 tight bore barrel, you will not be disappointing.

[hessu75]

It seems the mecha in my A&K SR25 was shimmed so crapply ( nice word eh ;-) ), that the motor height adjustment screw would go all the way in.

 

I am in progress of shimming the mecha with good instructions from Arnies.

 

I also bought the JG copy of the Systema Magnum high torque motor. It is recommended by quite a few users. LiPo, AB mosfet and high torque motor = win.

 

Luckily my A&K was already upgraded with tight bore inner barrel.

All I need is a nice scope on top this rifle now.