Powder selection.

[Col. Batguano]

it's the same thing in centerfires. They use faster powders in .223's than they do in bigger calibers like a 458 Win mag shooting a pill 10x the weight.

 

[dikman]

Being a relative newcomer to all this BP stuff, I was told (and have read repeatedly) the same thing - .50 cal and up use 2f, below that use 3f. My club recently acquired some 2f powder and carried out a lot of testing. They found that while it's certainly coarser than 3f, it actually shoots as well in some of their guns as the 3f they normally use (including cap and ball revolvers).

Any chance that old rule-of-thumb came about because of the quality of older powders?

 

[George]

And I think that if we ever figure out the reasoning behind the rule, it will involve the larger balls in larger calibers. They have more weight and more inertia, are harder to get started moving, so a slower push from larger grained powder results in less pressure.

I can imagine somebody deciding that .50-.54 was a good place to change powders for safety reasons. Since they didn't have, as far as I know, the ability to measure actual bore pressures at that time, I don't know how they made that decision, but it seems reasonable that safety was behind it.

Spence

 

[George]

They found that while it's certainly coarser than 3f, it actually shoots as well in some of their guns as the 3f they normally use (including cap and ball revolvers).

I'm not at all surprised at that, because I know of no reason it should be different. Consistent velocity is the key to accuracy, and that can be achieved with either grade of powder. I find no difference in my guns when I switch grades. In general, POI may change, but not group size.

Spence

 

[Wes/Tex]

Just to throw another chicken in the pot, when Elmer Keith interviewed the two old Civil War cavalry vets, they both mentioned loading up their Navy 6's with FFg and round balls. Have no idea how 1860's FFg compared to today's version but thought it interesting. Those old boys used it to advantage...suppose that's all that's all that counts!

 

[Ken Cormier]

I use 3fff main charge and prime works for me.