The Sights on the AR-15, even if a NM front sight in military configuration leave a bit to be desired, as I recall.
The Bushmaster has a reputation that would not deter me for a second, as to all I've handled.
Please tell me about the sight arrangments on the weapons. If they are NM and intended to be "Service" Rifle, they will not match those on your present M-1 or on an M1A (essentially the same).
Also, do you plan to shoot out to 600 yds?
The Mouse gun can do it, but it looks as though loading two different length cartridges might be how the Camp Perry Ites are handling this.
The sight radius on a "service" AR makes it a bit hard to compete (it is shorter) with the M1A's.
If you are only shooting to 2-300 yards on "simulated" 600 yard targets, it is not quite so critical to use the heaviest match .224 bullet.
Let me know.