"This gun is a good gun. But it did have its flaws.
I've had this sniper for a little over a year now and have made some modifications and upgrades along the way. Several of these modifications are because of the flaws the gun used to have. Firstly, since the mag is located where it is supposed to be, there has to be a feeding chute from the mag to the hop-up unit. I experienced feeding problems with this, so I got rid of imperfection and burrs inside for a smoother flow of BBs. I also put more tension on the spring inside the mag to push the BBs a little harder.
The internals of the trigger box the box itself are metal and lasted for a while, but then the main lever inside gave out. There is no replacement of this part, as far as I know. So I machined a new part out of a solid piece of steel- just keep this in mind. The spring is powerful, but has just recently started to warp for me. The spring guide and piston of the bolt assembly are plastic. The positive side of this is it is a little quieter, but the negative is the spring digs into the base of the spring, making it unable to rotate freely. Although the parts work and the stock piston is ported, these parts should be upgraded.
The hop-up of this gun is nice and consistent from the start, but I've shimmed mine for a more secure fit, and r-hopped it. The gun was accurate to begin with, but now it has great range and accuracy. One thing to keep in mind, however, is that the bucking is unique to this gun, as far as I know. So be extremely careful with it, because a replacement would be near impossible to find.
So upgrades-The spring, spring guide, piston, cylinder, and cylinder head are VSR-10 compatible. Just about everything else is unique.
-Upgrade the stock spring guide to some sort of ball bearing one
-Upgrade the piston to one of higher quality
-Could upgrade spring if you chose to
-R-hop really helped me, but it is not necessary to be effective.
-Accurate out of the box
-Powerful (I recommend nothing lighter than .30g bbs, I use .32g)
-Relatively quiet, which is good for stealth
-Very sturdy, has a great feel to it
-Some feeding issues
-Lack of upgrade parts
-Heavy (Gets tiring after running around)
Overall, out of the box, I'd give this gun a 4/5 because it works and gets the job done. After a few upgrades, this thing becomes a beast and deserves a 5/5