re: If you want to own an AR-15, you should build it

To prevent losing springs, put two hi back chairs at each end of a coffee table. Put a white towel on the coffee table. Hang a white sheet over you and the two hijack chairs like a tent. If a springs shoots out of your project, and it will at least once, you will easily find it and also see where it goes as well. fYI only. It worked for me.