The 308 out of a 24" or longer barrel is just a marginal 1K gun, with 16" to 20" barrels it's a 600yrd to 800yrd gun. It's best no matter what caliber you are shooting to keep the bullets above transonic, and it's hard to that with a short barreled 308. The top shooters can make the 308 shoot well past 1K, but I don't think the average guy can.