A friend in Belgium is building a 500/450Musket #2 on a Martini Action. The gun is at the proof house in Belgium. To have it proofed he needs a 10 ton load using a powder other than IMR3031 which is not available in Belgium.

The only load data I have is from Wal Winfers book on Westley Richards that shows a load of 52gr. of IMR3031and a 500 gr. bullet.

Is there any one here who loads for this cartridge who can provide load data?

I have genrated load data from Load From A Disk, but I find the program not very reliable.