Janissary
32 Cal
Well I think I found my answer. I found this paper which looked at historical examples and measured velocities of an 18.5mm ball out of 18.7mm, 19.5mm and 20.4mm barrels.
https://dspace.lib.cranfield.ac.uk/..._of_seventeenth_century_musket_balls-2019.pdf
Based on this paper, both 0.5mm and 1.5mm windage (equivalent to 0.570" in a 15mm or a 16mm bore) appear to be within the range of historical accuracy, but there is a significant reduction in velocity with more windage. I did a curve fit to the data and estimate that using a 1.5mm bore as opposed to a 0.5mm causes a reduction in velocity of 8% if shooting with a wad, and 15% if shooting wadless. Importantly, the tighter bore without a wad creates more muzzle energy than the larger bore with a wad.
Also, they reported that more musket ball mass was lost with larger bore diameters. I guess when the ball is bouncing around more violently inside, it loses more mass? It's only a few percent but still worth noting.
https://dspace.lib.cranfield.ac.uk/..._of_seventeenth_century_musket_balls-2019.pdf
Based on this paper, both 0.5mm and 1.5mm windage (equivalent to 0.570" in a 15mm or a 16mm bore) appear to be within the range of historical accuracy, but there is a significant reduction in velocity with more windage. I did a curve fit to the data and estimate that using a 1.5mm bore as opposed to a 0.5mm causes a reduction in velocity of 8% if shooting with a wad, and 15% if shooting wadless. Importantly, the tighter bore without a wad creates more muzzle energy than the larger bore with a wad.
Also, they reported that more musket ball mass was lost with larger bore diameters. I guess when the ball is bouncing around more violently inside, it loses more mass? It's only a few percent but still worth noting.
