Essentially a gun only has a narrow frontage: you only have to move an inch or two across its front for it to get a free shot! Seems a little odd given how cumbersome a cannon is and how briefly the target is in its line of sight...
Hopefully this pic shows my my issue: essentially if Blue advances forward the cannon cant fire traversing fire at it, but apparently if it follows the hypotenuse the cannon is allowed an extra shot (but the faster firing Red infantry still cant!)
This seems a little crazy and rather disproportionate given the tiny difference in the angle of approach! It was probably only really a problem cos we had rather a lot of small guns pottering around but guns do seem rather nasty in this situation! I do some times wonder how anyone closes up to their enemy in blackpowder!


