My vote for a factory barrel is the .260 Remington.. Factory .243 barrels, of which I have one, are 1 in 10 twist, which at pistol velocities is too slow to stabilize heavier 100 gr bullets. If you want to stick to 85 gr bullets the .243 is a good choice.
The 1 in 8 twist for the .260 Remington does a better job (for me anyway) of stabilizing the 120 gr bullets for deer size game. I shot 3 deer this year with the .260 and was satisfied. I chose to shoot for the rib cage and leave the shoulders in tact for eating, so they did not "drop in their tracks" so to speak.
Good Luck, Rol
The 1 in 8 twist for the .260 Remington does a better job (for me anyway) of stabilizing the 120 gr bullets for deer size game. I shot 3 deer this year with the .260 and was satisfied. I chose to shoot for the rib cage and leave the shoulders in tact for eating, so they did not "drop in their tracks" so to speak.
Good Luck, Rol
