Better to give a barrel a light clean job after every round or a through cleaning about half way ? What I have seen is in the first 20 or so rounds the accuracy and spreads will be good and as you foul the barrel more on some guns the speeds will increase and move you out of a node. The fear of the first being out of group after a barrel is cleaned because some matches I shoot in you have no extra rounds for foulers. Most of the matches are 50 to 60 rounds. DG