Hey guys. I’m really wanting to build a precision ar on a small frame. I’m probably going to go with a aero precision upper, lower, and atlas one 15” rail. This will be my first precision AR and I need some help deciding on what caliber. I’ve been looking at .224 Valkyrie, 6.5 Grendel, and 22 nosler. This gun would probably be mostly for target shooting and maybe shooting the occasional Whitetail. Any input would be really helpful on deciding this. Other things I’m not really set on are barrel make, length and twist. Any additional info on this would be helpful too. Thanks guys.