Thanks for the suggestions. I did try to source some Dyna Bore Coat locally, but couldn't find anyone who sold it. Tried Sinclair International but they can't send it through the post. Anyway, I just got back from a session at the range, and after a thorough clean with solvent then a good polish with JB paste
(again!), I shot a couple of reasonably respectable- 1 1/4"- groups of 200g Woodleighs over 44g of Benchmark 2 sparked by Rem 9 1/2 primers in Fed cases. I then switched to the same load with Federal 210M primers and the groups shrunk by half!! Beautiful cloverleaf 3/4" @ 100 meters. Perfect shooting conditions for a change - 20 C and no wind. Might take this load hunting in the near future!
Cheers,
John