I am really contiplating an AR soon but really wish to shy away from .223 because I would like to use it for deer and other game. Now I have seen the 6.8 and 6.5 out there and the Remington R25 in 7mm08 to .308. All in all I guess the rifles are basically identical except for the caliber. How does the 6.8 stack up to 7mm08 and 7.62x39 in these platforms? Or should I just opt for the .308?