The .260 Rem should be about right,but the barrel may need to beset back a thread or two.the Arisaka may not be pretty but it was the strongest action in P.O.Ackley's blow up tests #2 was the 97 Arisaka!Arisaka 38's were chambered for 7x57 for the Mexican Govt. and they never paid for them during their revolution and for the Thai Govt. in 30-06 after WW2.Midway USA has Bennett+ Adams barrels chambered and pre-threaded in various calibers.Food for thought.............Harold P.S. the first chrome plated bore in a military rifle was the 7.7 Arisaka