Buy a flat top upper receiver you can get a detachable carry handle. You can mount an optic on a rifle with a carry with the right kind of mount but its kind of awkward. You are depending on the nut in carry handle mount to stay tight. The flat top is better because I can add a carry handle or mount an optic right on the receiver and the mount is going to keep it there.
Have a nice day at the range
NRA Life Member