When is an actual "Varmint" rifle warranted vs a regular or sporter rifle in the same caliber, same .223 Rem? It seems the "varmint" rifles are often times much heavier due to the heavy longer barrel. Seems as though a sporter style rifle in .223 will put down a chuck just as fast as a varmint rifle in .223. Is it frequency of shots? Does the longer heavy barrel make them that much more accurate?