This is a pretty good price when you add up the cost of the extra upper, ciener kit, mags, case, etc. I had one of these J-15 conversions (Mine was done by Bushmaster) and it worked 100% with the A1 (SAFE,SEMI,FULL), A2(SAFE,SEMI,BURST), and M4 Enhanced(SAFE,SEMI,BURST,FULL) trigger groups. These lowers are cast so they may not be quite as rugged as a Forged lower guns but they are also much less expensive! The lower will be mil-spec so the owner can purchase just about any upper, trigger group, or other part and mount it to this weapon. With the Ciener kit, the M-16 is a weapon that you can afford to shoot all afternoon and is actually more fun than a 223 upper in my oppinion!
I wish I had the money as I would buy this! Prices on M-16 have climbed significantly now that Shrike is making the belt fed uppers and this lower would mount up to such an upper just fine!
Good Luck with your sale!