Do you have any lowers lying around that you do not have an upper for? I had parts to build out 2 complete lowers with a charging handle and BCG (223 or 300 BO) for one of them. I wish one was for a Glock 9 lower.
I tried to play that game before…keep some spare receivers put back in the safe. Always ended up raiding my spare parts stash and those stripped receivers turned into builds, then, I’d have to replenish my parts inventory.
Now, I just keep a stock of parts on hand and no receivers.
No need to keep spare lowers, or too many parts beyond the bare minimum for repairs, if needed. I have never had anything fail, though I know something eventually will. Spare parts aplenty and spare lowers WILL magically grow into full builds. It never fails.
Yep..box full of Sendra lowers XM15 / M15 marked, some other lowers, 80% Lowers (got cheap via group buys) AR15 / AR9 (Colt mag), boxes of parts, Colt Chrome BCG's, bunch of crap. Had more money than brains back then.