I would venture to say that twist, velocity, etc., has nothing to do with the fact that your rifle will shoot the 180's well, but not the 165 load you have had trouble with. I suggest that your rifle does not like that particular load (maybe not the specific LOT of that ammo you have), and that your rifle, if accurate with a 180-grain load, could be made to shoot a 165-grain bullet well also! It might require handloading to find the right combo, but there could also be a good factory load that would do well. By the way, there's very little difference between a 165-grain bullet and a 180-grain load!! Like 15 grains, about the same as a .22 caliber air-rifle pellet!!

Keep yore powder dry!!