About ten years ago on the EE I saw a SP1 minus receiver being sold and promptly snapped it up. Probably my best buy off the EE ever.
Pic of said SP1.
I imagine a few of you have seen the result posted several times over the years. I stuck those parts on a STAG receiver and added a Lone Star front handguard, putting the triangle HG up to protect it.
I finally found a cheap FFL to do transfers that lives a couple blocks away from in the same neighborhood and so I broke down and ordered a NDS-601 lower to finish off my SP1 parts. That now gives me a extra receiver to play with. About the time I was ordering from NDS I got a email from CBC Industries who was having a 30% off sale. An idea had been niggling at me in the back of my brain that I could build a inexpensive little paper popper around that receiver. In addition to the receiver my spare parts box has lots of A1 grips(my favorite), a couple A1 buttstock assemblies and some other assorted parts. I bought one of CBC's 16in uppers with a 13in keymod free float HG in 1:8 twist. I also picked up a RA-140 trigger, Aero Precision LW scope mount, a Vortex 4-12x40 BDC Crossfire II scope, AIM NIB BCG, CH and a triggerless LPK.
Since I took took today off for my B-day I decided to assemble this morning. I am on vacation next week so I should have plenty of time to get to the range. I have a 20rd mag with 52gr Black Hills Blue Box, a baggie with about 30rd of Radway Green 62gr, a couple boxes of PPU 75gr match and a couple hundred rd of Israeli TZZ 55gr surplus to test out in it. I plan to sight it in with the 52gr BHBB and then see what happens with the rest.