I think I've got a couple of the AR-10 "field repair kits" laying around Jgun. I've just gotta dig thru the gun box to verify it. If not, I know that I've got a complete BCG that's waiting on BATFE to get off thier ass so that I can finish building my shorty AR-10. Either way, I think I've got you covered. Just let me put my hands on it before I promise 100%. When I find it, you can PM me with your address and I'll drop the spring in the mail. Ron