So much for letting a gent rest on his laurels Awright, I'll see what I can do RE: the dime.
In all seriousness, to dellet's point, during workups I did push the ladder out to 18.2gr:
Primers were slightly flatter than normal, but most significantly the grouping opened to 2.52MOA. Now, I'm not a solid enough marksman to write off trying it again - may have been a bad day that trip. It's good to have a proven baseline for my rifle though, that's for sure.
...But I'm thinking the dime challenge is going to take precedence once I get off my butt and make some more!