If the barrel makes contact in the barrel channel then it can affect the groups as the barrel warms up.
Even though the barrel/wood may not make contact while you're checking it, what about when you rest the forend on a block of wood, or a back pack or bipod. Contact isn't good.
I think some barrels are affected more by heat than others.
I used a credit card to check for barrel to barrel channel clearance.
I removed some wood from the stock where it contacted the receiver and about 1.5 inches in front of the receiver.
Then we put three coats of release compound on the receiver/barrel (removed the trigger assembly and mixed up the acraglas).
Took it out of the stock the next day, cleaned the release compound off the metal and bedding compound and put it all back together. After that, with 50 grain bullets that little sporter barreled .222 Remington would put 3 shots under a dime at 150 yds. I wonder if my buddy still has it (that was over 30 years ago).