don't know the exact weight but it's pretty darn heavy compared to a regular ar considering it has an HBAR. owning both a piston and gas operated m16 i really don't see an advantage/disadvantage on both, i think both are just as reliable as each other on regular use and if maintained properly unless of course you put it on a stress test then that's the only time you'll really see the advantage of a piston. since i just go to the range for fun then clean my guns as soon as i get home and have guns incase of SHTF situations, i don't really need a piston system so i think i'll sell it and replace it with an ak47 or m14 instead. if only 7.62 ammo was so hard to find and expensive here i'll probably only have 1 m16/m4 instead of 3.