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Discussion Starter · #1 · (Edited)
I have two CMYA Platinum SR25 AEGs: The CM.098B SPR and the CM.098C M-LOK 16.5" version with a 21.1" inner-barrel. Looking to build-out the M-LOK version and keep the SPR more or less stock (perhaps a motor-swap).

Build-goals for SR25 M-LOK DMR:

A. High-FPS (e.g., 500+ @ .25G).
B. Range.
C. Accuracy.
D. Make AEG as quiet as possible (e.g., internal components + functional suppressor).

Starting parts list:

1. Siegetek GEN2 20.8:1 gearset [18:1 is stock] for elongated gearboxes ($140).
2. Lonex spiral-bevel + helical-pinion ($24.99).
3. Tienly 25K or 30K high-torque motor.
4. Neoprene or Sorbothane pads.
5. Which spring?
6. Which hop-up/packing/nub?
7. G36 nozzle: Which type/brand?

Any other CYMA SR25-specific parts recommendations? Full-auto ROF isn't a consideration since this will only be fired in semi-auto. The CYMA's stock parts are already pretty decent so only key parts need be considered.

However, gun comes with a factory-installed ETU/FET (which I assume is proprietary); are these parts likely to present any fitment issues if introducing third-party gearbox components?

I assume an aftermarket hop-up/packing/nub is also recommended. But since the gun already comes with a brass 6.03mm inner-barrel, I don't necessarily need to replace the barrel, but hop-up-to-barrel fitment is more or less guaranteed if I buy them as a complete assembly, right? [If I hire-out this build (likely), this is less of a concern.]
 

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Get a baseline performance read on everything first beforehand. You'd be surprised at how much can be done without throwing large amounts of $$$ at things. Immediately swapping internal parts usually leads to a bad time. Again, you'd be surprised at what doesn't need replacing.

After market parts won't necessarily interfere with your ETU. The question here is can your ETU handle the increased electrical loads that your desired performance specifications are going to put on it?

You don't need a set of Riots for a build like this. Also the helical Lonex gears are incompatible with Riot gears irregardless.

As for your hopup and barrel group; nothing is guaranteed to fit. Selecting parts from the same make can reduce your chances of tolerance stacking issues, but those will always remain. My preferred barrel group consists of a stock (assuming it works as it should) or Lonex hopup with either a 50 or 70d packing, a quality barrel and an IR-hop patch + M-nub. This combination has served me extremely well over the past decade or so and has always provided excellent performance.
 

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A cyma platinum is "tm compatible". That etu can be swapped for a perun or gate unit. And it is encouraged to do so, as that stock etu will blow when used in its stock configuration on an 11.1.

The stock compression parts are fine in a cyma platinum. Why do you want a new nozzle?

Helical gears are noisy and hard to shim.

A PDI 260% could get you that fps reading. But you are risking cracking the shell. Especially if you run it full stroke. But then again, why would you not? The whole point of having a SR25 platform (from a tech's standpoint) is for that increased air volume.

The Tienly 30k can pull a m190 on stock gears, with the Tienly 25k being able to pull a m210 on stock gears.

I do not think you need to worry about buying new gears. What you should focus on is getting a gearbox that can handle the amount of stress that you want. ie. CNC Aluminum shell. I would try to avoid retro arms as we have not yet proven if their product is fixed yet.

Maple leaf packing, all the way. What you want for this build is the MR Hop with an Omega Nub. You may want a new barrel as well. Something like a 6.08 or so and made of stainless steel or palsonite steel. That will take care of your range and accuracy.



Honestly, I would just try to quiet the system anywhere there is noise, replace the mosfet with a Perun Hybrid, install a Tienly 30k, add a new barrel and maple leaf hop packing/nub, and maybe add a new spring. Unless you invest in a cnc aluminum gearbox, adding a strong spring will cause your parts to die off really fast. If you do decide to get a cnc gearbox, we can help you build the platform a little more. But I am not risking someone else's gun because I said something that caused too much stress for the system and made it break.
 
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Discussion Starter · #4 ·
Hey, thanks for all the info, guys! I test shot the rifle for only a few dozen rounds shooting .50g BBs. Curiously, accuracy was fairly inconsistent (packing breaking-in?). Attempting to zero a 3.5-10x scope was nearly impossible because shots kept shifting up/down and left/right. My other AEGs generally shot lasers right out-of-the-box (e.g., KWA, ICS, etc.).
 

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Could be a dirty barrel?
 
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Discussion Starter · #6 · (Edited)
Aha! I'll clean it first thing tomorrow. Also, both SR25s were on sale so I don't have much invested in either ($225 for SPR; $253 for the M-LOK); i.e., so if I blow one up due to anyone's suggestions, I won't cry too much (or lay any blame). They are gorgeous riles, however.

As for compression, I was getting out-of-the-box numbers at an average of 370FPS with .25g BBs (rated velocity is 400-450FPS with .20g BBs), which seems good but not necessarily stellar for a 20"-barreled, extended-gearbox AEG (i.e., probably in the low 400s for .20g BBs, which is at low-end of the rated-spec).

Yeah, I was looking at the Retro Arms' CNC gearbox shells. Those appear to be quite good. Don't know if they make an extended shell though. Also, strike the helical gears, based on both your comments [and, from the Ben's comment on the topic from another thread]:
. . . Helical gears are from a different time, they are for the old weak motors and batteries when you needed to pull a heavier spring.

These days you can literally pull a m150 on 10:1 gears with neo motor and lipo.
I had initially thought helical gears were one of the components which would contribute to a quieter power-train (one of the principle goals for this build).
 

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If you want quiet you can get a lonex spiral bevel/pinion. In any aeg like 60% of the sound is the pinion and bevel meshing. Then like 20% is the rack meshing, some pistons mesh better with some sectors. Then the rest is the anti reversal latch clattering.

High speed gears have less meshing and are overall more quiet. But they aren't in no way efficient.

Seigetek gears are really nice, they are very strong and will survive anything. I recently ripped a rack out of my piston at 36rps. The sector still looked new even after the gearbox.

I've worked on some sr25s. Typically I just improve compression, shim, correct aoe on the piston and add some padding to the cylinder head.

Some events allow you to shoot 450 or even 500 with a "dmr"

As for accuracy, if it accepts a standard m4 hopup you could do a prowin with my hop up parts kit then use a lapped Prometheus barrel with a Elvish tac patch. That's probably the most high end accuracy upgrades you can do.

Stay away from the retro arms shells. Just radius your stock shell.
 

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I have two CMYA Platinum SR25 AEGs: The CM.098B SPR and the CM.098C M-LOK 16.5" version with a 21.1" inner-barrel. Looking to build-out the M-LOK version and keep the SPR more or less stock (perhaps a motor-swap).

Build-goals for SR25 M-LOK DMR:

A. High-FPS (e.g., 500+ @ .25G).
B. Range.
C. Accuracy.
D. Make AEG as quiet as possible (e.g., internal components + functional suppressor).

Starting parts list:

1. Siegetek GEN2 20.8:1 gearset [18:1 is stock] for elongated gearboxes ($140).
2. Lonex spiral-bevel + helical-pinion ($24.99).
3. Tienly 25K or 30K high-torque motor.
4. Neoprene or Sorbothane pads.
5. Which spring?
6. Which hop-up/packing/nub?
7. G36 nozzle: Which type/brand?

Any other CYMA SR25-specific parts recommendations? Full-auto ROF isn't a consideration since this will only be fired in semi-auto. The CYMA's stock parts are already pretty decent so only key parts need be considered.

However, gun comes with a factory-installed ETU/FET (which I assume is proprietary); are these parts likely to present any fitment issues if introducing third-party gearbox components?

I assume an aftermarket hop-up/packing/nub is also recommended. But since the gun already comes with a brass 6.03mm inner-barrel, I don't necessarily need to replace the barrel, but hop-up-to-barrel fitment is more or less guaranteed if I buy them as a complete assembly, right? [If I hire-out this build (likely), this is less of a concern.]
Hey, very new here and just now finally getting more serious with airsoft as I'd always liked to do.

I don't have my Cyma SR-25 yet so I can't tell you how these upgrades will perform, but I can echo my findings from my hours of impatiently searching for possible upgrades.

An r-hopped barrel, good quality bucking and nub have been widely suggested. Somewhat split opinion on the stock hop-up, but it is a rotary system so I'll give it a shot personally. I picked up a 509mm ZCI r hopped barrel with a modify baton flat-hop bucking "kit" off amazon from Elvish Tac. Really excited to test it vs the stock components.

There's a general consensus that the stock nozzle isn't 'all that' as it's lacking an o-ring. I forgot the exact size, but its something that ought to be replaced if you plan to go into the gearbox anyways. That being said, other compression related parts have also been suggested with the rest of the gearbox being left alone aside from shimming and the occasional motor upgrade.

These are my limited findings and I am far from experienced. But I hope it helps, the Cyma SR25 really seems like a great platform for the monies.

Best of luck
 

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O-Rings on Nozzle is not necessary. O-ring nozzles were used for alignment to minimize air turbulence...not for sealing the "system".

It is a false test where you test compression and you put the nozzle in too.

Also your AEG is not a closed system where it pushing against high resistance like a finger. It's blowing a loosely seated bb down a barrel.

Fluid Dynamics prove that Air Pressure does not move backwards in an AEG system.

The top makers know this too. TM, VFC and Krytac...all others...not so experienced. All their nozzles have no o-rings, but they fit well with no wobbles.
 

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O-Rings on Nozzle is not necessary. O-ring nozzles were used for alignment to minimize air turbulence...not for sealing the "system".

It is a false test where you test compression and you put the nozzle in too.

Also your AEG is not a closed system where it pushing against high resistance like a finger. It's blowing a loosely seated bb down a barrel.

Fluid Dynamics prove that Air Pressure does not move backwards in an AEG system.

The top makers know this too. TM, VFC and Krytac...all others...not so experienced. All their nozzles have no o-rings, but they fit well with no wobbles.
Oh okay! I really appreciate you correcting me there. I must have misunderstood the purpose of the o-ring being there earlier and assumed it was for a seal. But that makes more sense, similar to some of the o-rings/spacers on some inner barrels.

Would you even suggest upgrading the nozzle off the Cyma platinum gearboxes for the sake of a notable FPS consistency difference? Or any other compression related components?
Not to hijack the original post or anything, but my goal would be to make my shots as consistent as possible. Might end up pre ordering a Maxx ME Pro hop-up tomorrow if that makes any difference on parts choices/likely not to mesh well with the current nozzle.

Thanks again.
 

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If there are no compression issues, there is no reason to change the parts.

Most parts are not upgrades. And since this industry has no standards, mixing parts is Highly NOT recommended.
 

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If there are no compression issues, there is no reason to change the parts.

Most parts are not upgrades. And since this industry has no standards, mixing parts is Highly NOT recommended.
This is true. In earlier years i often replaced all stock internal parts since aftermarket parts would definitely improve performance i thought.

Welp with experience comes wisdom. Replacing too many parts can cause all sorts of fitment issues, especially in the air seal and hop-up area of the gun.

My G&G M4 has a stock nozzle with no oring and gets great consistency, with a Lonex M4 nozzle it gets poor consistency and feeding issues since it doesn't fit correctly. This is a Top Tech M4, their premium line and even there the nozzle comes with no oring.
 

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LEFSE is Master Level Airsmith for Airsoft.
 

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Maybe not quite master level, but I've learned from the many mistakes I've done over the years.
 

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So if I were you modular. You have a armory of guns to choose from to shoot in your backyard. Keep this one loud. Make it louder. Add a amplifier to it. Have it be you one to show off to friends as the loud one. My krytac lmg I added a amplifier to it. Mainly changes the sound. For playing yeah it makes me easier to find. But when playing when only lmgs get to go full auto its awesome to be the one making noise. Yeah they know where I am. But they know a ton of bbs are coming their way too. Wont scare the pros but kids might think twice. My other guns I want quiet as can be. But not this bad boy. It's my fun one. Shoot one of your many other guns in your back yard. You'll get another one next week probably anyways. Make this your loud bad boy :)
 

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Discussion Starter · #19 · (Edited)
Hey, thanks for all the replies! To reiterate, the goals are high-FPS, range, and accuracy; i.e., a super-DMR. So, an amped-up spring (plus any requisite accommodations), and improved hop-up. ROF is irrelevant since I will only be firing in semi-auto. Since I have two SR25s, yes, I would like to turn this into a super-gun as The Lords Hand suggests (though, not sure about annoying the neighbors even more).

I have several AEGs I will likely send out to one of the several qualified techs here rather than attempt myself, the SR25-build being among them. Someone needs to fix my ICS MP5 since I'm so lazy, I haven't even broken down the gun down yet to inspect. My other G&G MP5 is worth a complete overhaul since its externals are quite good, better than the ICS' (which aren't too shabby either).

I would like to make my G&P DDM4-A1 my "silent-killer," as quiet as possible, ideally with a custom built, functional suppressor. My KWAs shoot so well out-of-the-box, they don't need anything at all. I would also like one high-performance M16: I have a MOSFET-editon CYMA M16A1 and a budget-A&K M16A3 which I may replace with a CYMA Platinum, G&G, or ICS when available. Was the G&G the one with the most authentic M16A1 receiver?
 

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No that would be G&P. And you just can't go out and buy those receivers...
 
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