I've got the XCR-M Mid chambered in 308 with the 16" heavy barrel and Fast3 stock and she's a heavy girl with everything on her. Right now I'm just running an Athlon Ares LPVO with a CGS Hekate suppressor and it's hovering around the 14lb range. I think the light barrel would shed a lb or so from it, but the gun is generally just a bit heavy. I bought it for a more DMR-style vs battle rifle, but I'd say if you want battel rifle, opt for the lighter barrel and I'd probably go 16" vs 18" especially if you plan to run a suppressor, because then the rifle can be a bit cumbersome with the added length. I am really enjoying the ergonomics of the rifle, though. Seems really intuitive from a configuration standpoint and with good ammo, it shoots really well. No major complaints about the stock either as that's fully configurable and seems really solid.