Good on yer mate! May I suggest that you get a little book called "The Paper Jacket" by Paul Matthews. Although written for BP shooters, it will help you to get a better, more consistent wrap, and that will quite possibly reduce group size without you changing any other parameter. The best BP shooters get down to 2MOA under competition conditions (i.e. prone, sling allowed but no rest or wrist support, limited time).

And weigh the bullets too. Deviation should not be more than +/_ 0.5 gn around a median value. Tighter would be better, of course. Too high could mean that the mould was not quite closed when casting. Too low usually means bad filling and/or voids. Voids in particular will cause an off-axis center of gravity which spoils the flight, so be quite ruthless in putting out-of-tolerance bullets back into the melting pot.

Patrick