10 years ago the conventional wisdom was that a .308 with a barrel less than 16" was the ballistic equivalent of a very loud 7.62X39. Thanks to advances is modern ammunition, that has shifted some. Yes, there are loads that expand out to 100+ yards such as the MK319Mod0. No, they will not turn a 13" SCAR-17 into a 500 meter gun. You need decide if such a gun fills your needs despite the drawbacks. I did the calculus and opted to leave my barrel at 16".