'KALASH (Boyi)' full metal M16A4 RAS AEG (5581)

i got this gun about a week ago, and it's a good gun. externally. really, the outside of it is beautiful. it might be worth buying just for the body. everything is full metal except for the stock(which is really crappy) and the handguard(which is fine, you won't break it).
it was really loud when i first got it and from what i can tell, this is not going to go away without a lot of upgrading. it's toned down a LOT, but it's still not my g&g.
right off the bat it will need a shim job, and some work on the piston. the angle of engagement is pretty bad. if you don't do any work on it you will need a new piston in about 1-2k rounds(imho). you will also need to regrease. i suggest either replacing the piston with a longer(but not necessarily stronger) spring, or adding a couple of washers to the spring guide. the stock spring is really short and stiff. if you don't replace or otherwise space it out, you will have a really annoying "twang" sound at the end of every semi auto round, and every full auto burst. you should also put in either 7mm bearings, or 7mm bushings. the stock nylon bushings will fail after awhile(it would probably take about 2 months of weekly games, maybe a little longer), especially if you shim since you will get a much better rof.
all in all, this is a great gun IF you are comfortable working on a v2 gearbox. a techy will be able to turn this into something durable and nice for about 20-30$.