I own the CYMA 701b. Purchased from Taiwangun for £80.
To begin with:
If you are comfortable to lay down, wait for about 30 minutes for one kill, and move on then carry on.
Onto the gun itself:
The Gun breaks into three sections,
The furniture is Plastic, make no mistakes. As such it is very light, this can be fixed by using weights / poly filler or whichever. (I actually would suggest using filler of some kind, as it removes the reverbrations of sound from inside the furniture)
The Barrel / Trigger Mech / Cylinder are the heaviest parts, and in balance it easily requires a strong support arm otherwise you're going to have a bad time balancing.
There is a trigger guard which comes seperately and requires you to attach it to the trigger mech before then attaching to the furniture. Three screws, farily secure with no movement.
As for upgrades, this will completely accept VSR10 uprgades. - Check here for a complete list of parts / and a guide to doing so.
It fires (Chronoed personally and at shop):
.2 = 490 FPS
.36 = 365 FPS
For aethsetics you can potentially buy a M700 wood furniture for this, and with a little bit of work, it will sit snugly.
As for the mags comment above, you get 3 with the gun from TWG and each one after is £10 a pop
My main concerns with the rifle out of the box?
It has a crimped metal cylinder. This WILL become fragile and break with wear, So I completely suggest changing it sooner than later.
It is light, as mentioned above.
There are no sling loops.
Anything you would like to know specifically?