i have decided that this will be the first year that i will harvest a whitetail. i have a marlin 336 and was wondering if the 150 gr. was better than the 170gr. i will be hunting a farily wooded area and dont plan shooting farther than 100 yards. will the extra 20 grains provide extra knockdown power? also, can some recomend some good bullets, or should i just pick some up at wallyworld?