I also use the 165gr in everything .308 cal except Elk
I am jealous, I always wanted a Winchester M88 in .308 Win. If I can have all my wishes it would also be a carbine version with the 19inch barrel. I think that Winchester is using a 1 in 12 twist for that rifle and you should get good accuracy up to 180gr. That is as heavy as you would want to go anyway with it's case capacity. How is your trigger on your M88, I have handled a couple that were not the greatest. I admit to being a trigger snob.