I bought my Bushmaster AR a few years back...NIB @ $750. I'll never sell it.
Now I'm buying a .22 rifle to compliment my .22 pistol while I sit on my .223 ammo.
If you have not bought the .22 rifle yet, what you could do for about the same price is buy a .22 upper for your AR, then practice with the same trigger group you use for shooting .223.