you will here a lot of different opinions on glass bedding. here is mine.
first of all i have been doing this for over 30 years so i have learned a few tips . first of all if a rifle shoots fairly well & is not free floated i first pull the action out of the stock & shim the recoil lug just high enough to get a free float on the barrel. you can use anything like thin cardboard,but be carefull not to loose the thread grip on your action screws. this eliminates going to a lot of work & expense just to find out the glassing & floating didn't help your situation. now go to the bench & try a few rounds, if you gain tighter groups then go all the way,glass bedding ,floating ect. there are even a few more tips if this still does not help..
mark a sipes