6br shot out at 1200 rounds

[Robinhood]

I have not seen as bad a change, but, mine slowly opened up to more than 1/2MOA over about 1000rnds. Finally the light bulb went off and I loaded some a little longer and voila! Back to smaller groups. I'm using the 103gn Vapor Trail machine made bullets.

This^

[Fuj']

Besides the throat eroding over time, so is the leade. That leade must be perfect to the
rifling. If it does not erode evenly, which it wont, the engraving will be uneven and will
effect accuracy....And don't forget the crown. I'll normally re-crown 2 more times over the
life of a barrel I compete with.

[charlie b]

How far back do you cut a crown, or is it just enough to 'ream' the crown to refresh the edges?