Get another AR15 or just get a different upper?
So as much as I was excited/into/intrigued by the M1A and the mighty 308 round, in a moment of self reflection, I realized it's an absolute want and not a need.
So then my thought goes to getting another AR15. I like the 223/556 round but I am interested by the 6.8 SPC and.458 SOCOM and other rounds.
What would be the advantage of getting another AR15 vs just buying another upper?
Also, on a separate note, how much different is the M&P Sport to a "milspec" AR15? (I know about the barrel/dust cover/forward assist, but how about the internals?)
Open to general speculation or specific suggestions.