The 6mm definitely provide a slight edge. I see it in the score card very often. Take a years worth of matches and 6mm will be at the top at least 70% of the time. You'll have 6.5's in there as well or even an occasional 308 or some other cartridge, but the majority at the top are normally 6mm.

The fact is if you take someone who was highly competitive with a 6.5 or 308 and give them a 6. Their scores will further improve simply due to the increase in the hit percentage within 800yds which is what most of our shooting is. At 800yds and in you could say the following, 308 has a 60% chance, 6.5 has a 70% chance, and 6mm has an 80% chance of hitting. That's difference in the calibre choices for tactical precision matches.

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