Nice! That will be NOTICEABLY lighter than a standard M4-ish gun. I'm at 3lb 15oz with mine, with optic. :-)Partially assembled with M4 upper, upper not fully tightened down because I'm waiting to get access to a vice (mine's not attached to anything at the moment!) to swap this M4 upper to my .300blk and use the PSA slickside upper that that gun is assembled with.
Current weight is 5lb 2.7oz. With the standard M16 carrier, the aforementioned M4 upper, and still has the A2 stock spacer. I expect to cut ~2oz from the carrier. The slick upper weighs 5.95oz vs 8.6 for the M4; so 2.6oz there. The spacer weighs 0.8 oz.
So I expect 4lbs 13.x oz.
If I move to the TN Arms hybrid poly lower that will shave another 3oz + the weight of the trigger guard.
Other note, I don't have any optic or sights on it yet.