"Excellent piece. Worked on a few of these and the other m4 platinum line guns from CYMA; thoroughly impressed by its performance and quality. Internals on the SR25 are great: rotary hop up, metal rack piston, neo motor. I upgraded mine with better barrel and bucking, new spring, some external bits to make a m110k1 build, o ring air nozzle (SHS G36 one is the right length). Shoots excellent and only came out to ~$500 with some extra mags and the external extras.
"You don't need to shell out $800 for a full DMR build with fancy bells and whistles. If you're on a budget, this is the best out of the box budget DMR you can buy. I got the 14.5" MLOK version when it was on sale and it's quite possibly the best $200 I've spent so far. I'm just surprised at how many features CYMA has packed into this thing. 6.03mm tightbore inner barrel, H-mound hop up bucking with rotary adjustment, reinforced V2.5 gearbox with steel 19-tooth rack polycarb piston with aluminum bearing piston head, aluminum double O-ring cylinder head, CNC steel 18:1 gearset, 8mm steel bearings, neodyminum high torque motor, in-line trigger mosfet, and quick-change spring with ball bearing spring guide.
Externally it sports an aluminum handguard, smooth matte black aluminum alloy billet-style receiver, metal ambidextrous selector with the right side selector shaved by 1/2 to make space for your trigger finger, metal magazine release, metal trigger, metal flat top rail, and polymer stock/grip. The charging handle is also metal and locks open the mock bolt, which can be released with the left side bolt release. The magazine is a high-capacity 470 round wind-up PMAG style magazine. The gun should be compatible with most non-ARES SR-25 magazines. The finish on the gun is supposedly weather-resistant, but it does feel like it can scratch easily so be warned.
The performance is spectacular to say the least. The first thing you notice is how light the trigger is and how responsive it is. The trigger response on an 11.1v lipo is better than most VFC AEG's and on par with Krytacs and SSG builds. There is a decent amount of uptake on the travel but the last 1mm or so has an almost imperceptible microswitch-like "click" that actually causes the gun to fire. The response should be even better with a lower FPS spring. Speaking of FPS, this gun is shooting quite hot, at around 450+ FPS out of the box owing to the longer inner barrel and high cylinder volume which is inherent to most SR25 gearboxes. The airseal is alright and shimming appears to be good. The piston has 1/2 of the last tooth shaved down to assist with AOE. FPS consistency is pretty alright for a stock gun with deviations of about /-3 FPS. I believe the piston head seal could be better inside the cylinder but for $210 I'm not complaining. Barrel was surprisingly clean out of the box and needed only two swabs to remove all gunk. The crowning was not the best but I can't complain. Range is approx. 60 meters accurately on a torso sized target with some flyers, but that's most likely the bucking breaking in. Replacing your hop up bucking with an R-Hop and a flat bucking with flat mound will increase your range to approx. 80 meters with heavy bb's.
I have only two gripes with this gun. Firstly, the quick-change spring knob inside the buffer tube doesn't exist for me. There is only a flat screw cap that accepts very, very wide flathead screwdrivers or a thin metal bar like a hex key. Not a big issue. It still has a screw hole inside to allow mounting of other buffer tubes and stock assemblies. I attached a UBR stock on mine to give it a nice DMR look. Second, the flash hider is stupidly hard to get off as it is retained by a grub screw that is locked in so securely that it may break your hex key (like it broke mine). That's what dremels are for though. These cons are minor and I'm having a very, very hard time finding any fault with this gun that would otherwise ruin my airsofting experience.
One thing to note is that it does have full-auto function, even though there is no visible selector marking for that. You will have to find a way to semi-lock it if you plan on running this in a Milsim game.
-Great build quality, both internally and externally - minimal to no upgrades necessary
-Good accuracy and range out of the box
-Excellent, lightweight trigger with great response
-Rotary hop up unit for easy hop adjustment
-Charging handle locks bolt back, bolt catch actually works
-Ambidextrous selector with right side shaved by 1/2 for comfortable shooting
-Metal flip-up sights
-Comfortable pistol grip
-Retractable stock with decent space for batteries
-In-line MOSFET which can run 7.4 or 11.1v lipo's
-Good weight (about 7 pounds unloaded, balanced around the trigger)
-Quick change spring system
-Minimal upgrades needed
-Compatible with most SR25 mags
-Bucking could use replacement
-Flash hider nearly impossible to get off
-Quick change spring guide knob non-existent, need some sort of tool
-Stock wobbles a bit
-Paint may scratch easily
-HUGE magazines, need dedicated .308 pouches
-Need semi-lock function for Milsim events