The 24" barrel is the minimum that works well with the 7mmremmag.The 26" barrel will add about 80fps but the barrel length does not affect accuracy in any way.Thefactory 7mm rifles are commonlyavailable with both 24" and 26" lengths.Browning and winchester are two companies that use 26" barrels while some othersuse 24" lengths.Companies such as remington use either 24" or 26" lengths depending on the rifle model.