At the local club, 6mm barrels are doing quite well in long range competition.

The top shooter at the season's closing meet took the win with a *semi auto* in 6mm Rat against a pack of hotrod bolt guns. Gotta say though, I suspect it was much more the Indian than the arrow. Windy day there and great job by the rifleman.
Surely the skinny 6mm 108 Berger javelins helped at least a wee bit...