The 1 in 10 twist should work for you depending on what bullet you are going to shoot. Rember that the 260 is a 6.5mm bullet which are long bullets to start with . If you go to hevier bullets or copper bullets like the barns X they might require the faster twist rate . I shoot alot of 264win mag and it has the 1in 9 twist which works awsome with 140gr bullets... Hope this helps you...