SR-25 Mechanical HPA Build Help

[TobiasC95]

Hi Folks,

 

First time posting in any kind of forum. Hoping I can get some advice on a SR-25 build I'm planning on making HPA.

The base gun that I am going to be using is the G&G SR-25 E2 APC MLOK, when stock is available.

 

My aim from this build is to have a Mechanical HPA system, the one I have been considering as the main HPA engine is the Kythera as it's single shot only, and I like the idea of it being mechanical and no electronics. The G&G is semi only so seems to be a good match.

Secondly it would run either a HPA Stock or CO2 Stock, depending on what works best compatibility wise as I want it to be without a hose line/external tank. That is my main criteria really as I find this annoying with my wolverine. I know a HPA stock would give shot's better consistency, but C02 is better looks as I thought I could use my UBR stock from my other gun on this build.

 

Other tid bits of info I've already worked out is that Kythera need certain nozzles, and the one for my gun is the un branded one as its #1

Something I'm not sure on is if I need a spacer in the shell.

 

Lastly any advice on what internals and hop units I should use would be appreciated. I was think Maxx Pro as that seems to get good reviews.

 

Please let me know if I'm doing anything that's glaringly wrong.

 

Cheers

Tobias

 

 

 

 

From Tobias

[Impulse]

I'm not a fan of the G&G SR-25s because they're V2 gearboxes with weird nozzles; A&K, G&P, Classic Army and Cyma are all preferable from what I've looked into. From what I remember, the SR-25 Kythera is built with the A&K/G&P/Cyma gearbox and nozzle in mind. In terms of what you'd need for a G&G, I'm not really sure but it may be worth giving High Pressure Airsoft a call; they stock the Kythera and from my experience they can usually answer compatibility questions like this. I'm not as much of a fan of the mechanical systems myself, as they tend to be a bit louder and less customisable than their electronic counterparts, both of which I value far more than I value no battery and the gun being totally waterproof as I'm not about to jump into a swimming pool and play underwater airsoft with it; HPA electric systems are waterproof enough to where I took my m21 to last year's AI500 where we got battered by a heavy storm during the game and it was totally unaffected as the FCU was in the stock which was pretty watertight (though some of the people I went with had guns die on them in that torrential downpour because MOSFET + water = no bueno). Not saying mechanical HPA systems are bad and I definitely think they have their merits, but they're just not for me.

 

For the stock, I'd go with the HPA stock, not the CO2 stock. HPA is consistent pretty much up until you run out of air, but CO2 is reliably inconsistent. What I mean by that is the power tends to drop steadily over the course of the bulb depleting, rather than being consistent up until it really starts running on empty. I used to use a CO2 adapter for my VSR, using the Wolverine Bolt, as I wanted a HPA setup without a line or tank, but quickly swapped to sticking a very small HPA bottle in a stock pouch because I hated the inconsistency of CO2 and being a DMR/sniper, which I'm guessing is your goal with a HPA SR-25 even if you keep it to 1.1J, consistency is the absolute golden thing you want, and mouse fart quietness is a massive draw for HPA in these sorts of builds.

 

For other internals, I'm running a Pro Win rotary hop unit, but I imagine the Maxx units are pretty good too. I can't comment on it yet as I need to get my SR-25 off to my local tech (because AEGs are techno-wizardry and I couldn't do my gearbox modifications myself ), but I believe it's as good as anything. I probably could've stuck with the stock hop unit, but I had the funds, so I figured "why not?". For rubber and nub, I am a massive fan of basic Maple Leaf macaron rubbers (NOT the super macaron) and would generally advise 60 or 70 degree hardness with a layer or two of PTFE tape wrapped around where the rubber meets the barrel to make sure the air seal is nice and tight. For nub, Maple Leaf omega nub goes wonderfully with the macaron. I'd say I was getting about 65m effective range with a 60 degree macaron and omega nub in my HPA m21 build, launching .4s at 1.1J for no MED and hitting a man-sized target 9/10 times at that 65m range. Some would argue that's going overkill for effective range mandating 9/10 hits, but when you're being a sneaky sniper/DMR, you want all the shots to hit as if you miss your first shot, the enemy goes to ground and becomes a lot harder to shoot as they start to suss out your position, at which point they sling a wall of full-auto in your direction. Not ideal!

 

Sorry for my wall of text, but I do love my sniper/DMR rifles and I love talking about builds because I'm a perfectionist nerd.

[TobiasC95]

Thanks for your input man. You've really got me thinking about my build some more, I thought I was nearly there. Wall of text is appreciated, some sound advice. I do think I'm going to stick with the base gun though because it looks hella saucy and I just really like m-lok for the ease of use adding attachments and looks. (Which let's be honest, looking gucci is part of it) But you've definitely got me considering the other engines and hop up set ups.

 

Thanks

T

[Impulse]

One potential solution that I was going to put in my SR-25 before I decided to try it in AEG mode (to take advantage of the v2.5 gearbox the Cyma has) was to go with a Wolverine Inferno engine. It's an electrical one, so it will require a battery unlike the Kythera, but they do replacement nozzles for the Inferno (which is typically a v2 engine) to use it with some of the weirder guns, including the G&G SR-25

 

Obviously, HPA builds are pricey, so take the time and find exactly what you want so you waste as little money as possible . If I don't like my SR-25 as an AEG (I'm making it as quiet as possible), I'll be going with a Wolverine Inferno with this replacement nozzle in 2023 once I've given the AEG setup a good, thorough trial through the rest of this year (well, the A&K one for me as the Cyma is a clone of it or the G&P)

Edited July 29, 2022 by Impulse

[TobiasC95]

You bastard!   I'm on a different path now. So more research needed, but you have got me leaning towards a Inferno Gen 2 engine. Seems more of a drop in approach with less incompatibility issues, it's compatible with v2 gearboxes which the G&G SR25 is.

 

Also where did you come across your HPA Stock. I can't seem to find anything available in the UK, was yours an import job?

 

[Impulse]

2 minutes ago, TobiasC95 said:

You bastard!   I'm on a different path now. So more research needed, but you have got me leaning towards a Inferno Gen 2 engine. Seems more of a drop in approach with less incompatibility issues, it's compatible with v2 gearboxes which the G&G SR25 is.

 

Also where did you come across your HPA Stock. I can't seem to find anything available in the UK, was yours an import job?

 

 

I don't have an HPA stock. I use a 10ci tank (which is apparently now discontinued!) in a stock pouch. It pokes out a little bit, but doesn't really affect me as I can still shoulder it on the right (though not on the left, but I rarely set up shooting from my left shoulder. Not looking forward to if I have to replace the tank as I'd have to go 13ci which are longer and may not be practical in a stock pouch

 

I used to run the same with my m21, but for a semi-auto build it wasn't practical as 300ish shots with a bolt action will last me all day, but around 500ish shots with a semi-auto can be a bit tight. The only pic of my setup I have is with my m21, which I no longer do, but it's the same with my VSR setup:

 

In terms of HPA stocks I honestly don't know much about them, so you may be stuck with CO2 if you don't want a line and tank (even then I don't know much about the CO2 stocks, just the adapters). I know there's one for the MTW (Wraith Aero stock) as I know a guy who has one, but I don't know if they'd be compatible with something that isn't an MTW. I generally just run a tank in a backpack when I run my HPA m21 and it hasn't ever really been a problem for me. I can still sling it and the line never gets in my way, though I'd rather not have it, hence I'm going AEG at first with my SR-25 build.

[Lozart]

1 hour ago, Impulse said:

In terms of HPA stocks I honestly don't know much about them, so you may be stuck with CO2 if you don't want a line and tank (even then I don't know much about the CO2 stocks, just the adapters). I know there's one for the MTW (Wraith Aero stock) as I know a guy who has one, but I don't know if they'd be compatible with something that isn't an MTW.

 

There is a version of the Wraith stock for normal AEG as well.

[Kls77]

Easier to use a classic army . AK etc sr25 . 

 

They are cheaper too . And maybe a mancraft kit( which I use )  . With max hop and good barrel . 

 

U can use mancraft u shape adapter in rear so can change between co2 capsules or small bottle . Or unclip and use regular bottle . 

 

Mancraft also do a stand alone mech kit that replaces the gearbox . Which means is perfectly aligned evrytime for shot consistent

[Kls77]

My sr25 

Mancraft kit . Maxx hop . Flat hop . Edgi barrel . . Set for .45g