The only "data" I have is for a .75 shooting patched .715 round balls weighing only 545gr.

130gr. generated 1,136fps
150gr. generated 1,213fps

There is no pressure data with the loads and the powder in the 70' when this data was produced, was poor quality.

We can extrapolate or guesstimate pressures from this data if using the same powder as equal velocities produce equal pressures in this book's data.
LUP- lead units of pressure - copper crushers do not register this low with accuracy.

1,136fps generates APPROX. 4,400LUP
1,213fps generates APPROX. 5,300LUP

Using heavier conicals, in % ratio to the 10 bore's difference between round ball and conical, we get pressures as below using G-O 2F.

1,200fps generates APPROX. 9,450LUP

Now - what a 10 drams load would produce, I have no idea.

I've shot up to 7 1/3rd drams (200gr.) in my 14 bore muzzleloading rifle, generating 1,700fps. Other than kicking rather hard, no other problems.

From the extrapolations, this load generated only 9,100LUP.

If you were to get round ball speeds up to that level, they would produce about the same pressure.

At a more realistic 1,550fps, you might develop 7,500LUP to about 8,000LUP tops, which is very low indeed.

Even (or maybe especially) armed with all this guesswork, I would not build a rifle with steel having yield strength of only 26,000psi -

THAT IS SCARY!