I just picked up a Sig 516 rifle (black) in trade and have decided I want to change out the upper for a mid length set up; looking for a PWS MK 116. I have not fired the Sig so it is as new in box. I did however field strip and clean the whole set up to get it ready to go. Right now I am only looking to sell/trade the upper but I could be talked into selling the whole thing and building from the ground up. If you have a mid length piston (ie Adams Arms) upper let me know. Price out right for the upper is $900 or $800 without sights.