With 869 I dont think you will be close to compressing the load at 90grs. I have found good accuracy so far with it not being fussy with the OAL. I think it is one gun that you will want to find a suitable load for it and put it away and just use it for hunting, The gun weights 9lbs with scope and recoil isn't bad at all. I would compare it to a little less than a 270 Weatherby.
