I have several other rifles that were either separate, complete uppers and lowers that were mated to each other or complete uppers and lowers that I built and then mated with an upper. This is the first one that I bought all the parts separately and put it together myself.

I wanted it to be mid-length gas because I prefer it over carbine. I also wanted to use an FSB so that I wasn't spending another $200+ on a rail. But I also wanted it to have a few of the comforts I was used to on my other rifles.

I bought used parts when I could find them and new parts when I couldn't. I probably spent more money then if I would have just bought a complete rifle but I had much more fun this way and got the exact parts I wanted.

Upper:
BCM upper
BCM BCG
AXTS Raptor CH
16" mid-length Ballistic Advantage barrel
BCM A2 FH
Daniel Defense fixed rear sight
Magpul MOE SL handguard

Lower:
Ruger stripped lower
LPK I had in my parts bin
Mil spec buffer tube
Carbine spring
H buffer
Magpul MOE SL stock
Magpul MIAD 1.1 grip
Magpul trigger guard
Troy battery assist lever
BAD-ASS ST safety
BAD enhanced pin set

I'm pretty happy with how it came out. I may add a thing or two to it as time goes by though. Hopefully I can get to the range sometime soon to test it out and zero it in.