the other thing to consider is that at over 180 grains , seated to factory length , your bullet is seating IN the powder - not a good thing- with the 06, being a half inch longer is not-but if you can't kill it with 180, there's something wrong- and it isn't the load- or 165's for that matter-
308's can come in 3 flavors 1/10, 1/11, and 1/12- the 1/10 will accomdate it all, but you run out of case length at 190/200- ie it seats too deep, you don't get a 1/11 very often unless it's a custom barrel, and the 1/12 being the most common- and it depends on the manufacturer- my 742 remmy is a 1/10 and my savage 99 is a 1/12- i should imagine that's because remmy just takes an '06 barrel and chambers it for the 308- the action length is an 06 and the mag has a spacer in it- the savage on the other hand , is a purpose built 308- it's really just a updated 300 savage- lastly, i've got a little chart that shows minimum twist- and it says you need a twist of 1/13.8 to stabilize a 180 at 308 velocities-