The loads given by the manufacturer are based mostly in its desire to avoid products liability suits here in the USA, based on what materials it uses to make the gun. You don't want to blow up the gun, and neither does the Company want you to do it, either. Stay within the recommended load. A Conical has a lOT MORE WEIGHT( obvious to the casual observer) and ALSO A LOT MORE Bearing surface, which increases the Coefficient of Friction between the bullet and the barrel. Its that increase in C/F, and the resulting rise in chamber pressure that poses a real threat to blowing up the gun.
I don't know any BP gun where you don't load a lesser amount of powder behind a CONICAL(bullet) than when shooting a PRB, or even a bare RB.
Most pistols, and revolvers had military application before civilian use was ever considered by the makers. The military gave the short arms to cavalry units, and they were trained to fire with the front sight on the enemy's stomach, or BELT BUCKLE.
Pistols and revolvers, using fixed sights , well into the 1890s, were sighted in to hit dead on at 75 yds! At shorter ranges, the ball/bullet would strike higher, but that would put the projectile in the chest cavity, or neck or head, if the shooter fired too quickly, and didn't get that front sight down in the rear notch. Adjustable rear sights are a 20th century invention, for handgun use. Even the .45 Colt pistol was zeroed to shoot HIGH, and soldiers were still taught to aim for the belt buckles, in WWI.