Lancaster-

In this image

To the left of the roundball is a pointed projectile with 16 printed on it.

Will you please feature this part of that page and translate for us?
Is that a 16 bore projectile?

I think it might be similar to what you see in this paper cased 16b pinfire round.

Note this cutaway view from an old text

Are there other 16 bore projectiles from the mid-late 1800's in your textbooks?

--Tinker