Chaz,
I'd start with a Lyman Snover mould-I think it's the best of the commercial moulds for mid-range or silhouette shooting out to 600 yd. I think the Saeco 740 is the second best. I don't like any of the rest. The Lyman flat point bullet should be good for hunting.
If you can afford an extra $50-60, I'd advise a custom mould from Fred Leeth, either the Snover design (his carry more lube) or preferably the Gunn modified (this bullet has the highest ballistic coefficient, if you measure all the way out to 600 yds., and is the least affected by wind variations). Both are in the 410-420 gr. range.
I'd seat those bullets 0.010" short of the rifling, over a 0.060 vegetable wad, to start, and try 0.010" longer (just touching the rifling) and 0.020" longer (0.010 into the rifling) if the first try doesn't give you the tight groups you want.
After fire-forming, I'd back the sizing die out 4-5 turns or use a neck sizing die to avoid overworking the brass, and I'd get a 0.048/0.412" expander plug from Buffalo Arms.
I'd start with Federal 215, and try Fed 210, Win WLR if the first don't group as tightly as you'd like.
I'd start with either Swiss 1.5 Fg powder compressed 0.040-0.050", trying a grain less (probably 0.010-0.020 compression) and 1-2 grains more if the first load didn't give you the accuracy you desire, or GOEX compressed 0.200", moving up a grain at a time until you get the accuracy you want (it may take 0.300" or a little more).
The Swiss can be loaded without a separate compression step as long as you stay in the 0.050 range (I haven't tried more-you can try it, miking the front section of the bullets before and after to determine if you are bumping up the diameter-if you are, you need to use a separate compression die). The GOES definitely needs a compression die.
I've had and shot extensively two Shiloh .40-70 SS's, and both of them would shoot a load prepared in this manner. (Most other calibers do too.)
Hope this helps, and you shoot really tight groups.
Clarence
