I was watching guns&ammo tv the other night and they had the Bushmaster .450 on there it was one heck of a gun.But since bushmaster makes them,can you buy a bushmaster upper reciver and put it on a colt stock.They said that the clip size was the same as the .223 so you didn't have to get a new lower just a new upper.Just wanted to know if anyone has one or has got to shoot one,and wanted to know what you think about them.