RE: 85 grain, 100 grain, 125 grain
the main diffrencees are waight and size the pros of 85 gr. are faster speed the cons less stable less penetration 100 gr. pros mid penetration more stable more cutting diameterconsmid speed125 gr. pros most penetration mid stable most cutting diameter lowest speed
but this is out of my bow try each one in yours and then use your fav. (most people go with 100 gr.)