why replace a varmint caliber with another varmint caliber??? they'd lose more then gain by going to a much larger case that uses a projectile thats only half a milimeter larger in diameter then a 5.56. they would have to cut mag capacity down to 20 from 30 to accomedate for the fatter cased cartridge. not a good trade off in my opinion. honestly I think they had the right idea when the 6.8 spc was developed. also if they would use a 243 which is a necked down 308 why not just use a 7.62 since the ammo is already readily available