When I started on my M/N cast boolit venture, a few years ago. ( This has been an off and on again project) I went to one of the members of the gun club that I belong to. He was/is an avid cast boolit shooter and has traveled to many cast boolit shoots and has a few wins under his belt. He made a chamber cast in my rifle and showed me the technique to do so on my own, in the future.
Anyway, he recommended the 314299 mould to start with, as it was very close to my chamber dimensions. I bought anf tried this mould will varying results. I would get good partial good groups, (2"- 3") with fliers. These groups were fired at 100 yards. After reading the different postings on the CastBoolits since, I have decided to go with the boolit that fits the throat closer, the FAT 316299. Which leads me to where I am now.
The chamber has a long throat. The dimension is .317. The bore diameter is
.304, and the groove dimension is .313. I have slugged the bore twice for effect.
The reason I was asking about the harder alloy, is that I was wanting to try to get to the higher velocities. I have read by some that the ww+ tin alloy may skid in the fast rifeling.
There is a chart that recognises the different alloys, and matches the bhn to the different pressures created by ones loadongs.
I did recognize, and have known that the seating depth definately has a direct effect on accuracy. That is why I had shot three groups with the 17 grains of 2400 powder. One batch shot the best, and the only thing that was changed was the seating depth.
Keep em coming folks.
Jack