Scoring

Muzzle loading firearms eligible to compete in the same event are often available in a variety of calibers. For this reason and in short range competition (up to 100m), when scoring the centre point of shot holes must be at least 50% over the line to count for the higher score. This eliminates any advantage that might be gained by shooting a large diameter bore rifle against a smaller one and if shots only had to break a scoring ring to gain the higher score.
In the event of a tie the winner is the one who has the highest number of shots in each scoring ring in descending order. If these are the same for each ten scoring shots, then the loser is the one with a scoring shot furthest from the centre. If the tie is still unresolved the next nearest scoring shots are used, and so on.
Source: https://www.mlagb.com/competitive-shooting/