Quoted:
My bad, its a SIG .556 (yea I think its pretty obvious that I dont know shit about this rifle lol)... I was thinking of selling the rifle in the photo to fund it, good idea or bad idea? Also, how much more accurate is the standard AR-15 vs the SIG .556?
Good or bad idea depends on what you want to do with it.
I have both and I've found the AR to be more accurate. I was surprised, as I expected the SIG to win in the accuracy competition, but it shot about an 1/2 to 1 MOA greater than a stock AR carbine with the same Ammo. But I also really like shooting the SIG as it feels different than the AR. It seems a bit more solid and it shoots smoother than my ARs in both DI and piston. Follow on rapid fire shots with the SIG seem a bit easier to control. The SIG is WAY nose heavy with the stock fish-gill forearm - but I swapped them out for the 550 handguards and it feels like a completely different rifle now. I haven't done may drills yet with the SIG with the new 550 handguards, but looking forward to seeing how it shoots. You also don't get that annoying "sproing" sound with the SIG.
Having said all that, if I had to chose between my SIG and one of my ARs - I would take my AR. Its lighter, more versatle, more adaptable, has more options and is more accurate. But since I don't have to choose, I'm glad I have both.