furman,
I merely passed along to Raimey, Axle's finding that the burning rate of VV N140 is very close to R5( previously R5 was said to be between 3031 and 4064). This is useful info where you can find a load with R5, but I wouldn't try to extend the comparison to black powder. If I were loading for a 10x60, I would likely use Unique, 4198, or 5744, maybe 4895.
Mike