The H&H came with 10 rounds loaded with 480gr Woodleigh Softs and 77 grains of IMR 3031. CFA took one round home from DSC and I took the rifle and the ramainaing 9 rounds.

When I fired the 3031 rounds at 25 and 50 yards they hit high and wide. The rifle was sticky to open with some primer protrusion.
As I stated earlier this rifle had large flat firing pins.

My sources show 2 different 500/465 loads, one with 73 grains of cordite, one with 75gr cordite.

My first range session was with 86, 87, and 88 grains of RL 15 with filler.
88 grains shot best.

89 grains exhibited a small amount of primer protrusion, causing the rifle to be a litle sticky to open, no other pressure signs.
With 480 Woodleigh solids I fired 87 and 88 grains, there was very little difference so 87 grains was going to be the Solid load.

The last range session I was going to shoot at 25, 50, 75 and 100 yards. The rifle shot high with a very small front sight, it shot just about perfect with the "night bead" so I was going to figure out how big to make the new front sight.
All rounds fired prior to the right bbl letting go hit the paper properly and there were no signs of impending bbl failure.

I AM OF THE OPINION NOW THAT IT MAKES NO DIFFERENCE IN WHAT POWDER YOU USE. I think the problem lies in weak barrel steel.

The other 2 barrels that I have examined not only burst in the same place as CFA's H&H but split to the muzzle and one split back past the handguard slightly injuring the shooter.

What we really need to know is the year and maker of the bbls on as many burst incidents as possible.