[kronckew]

Cannons were usually fired with the muzzles outside their embrasures, and the heat, smoke and pressure waves were mostly (but not all) directed forward away from the crew, who learned quickly not to stand forward of the muzzle, or behind the carriage. A 'loose cannon' was a danger to all.

Any excess powder un-burnt outside the barrel is essentially wasted as it has no effect on propelling the projectile, just in making noise and heat. Establishing the correct charge would require a few firings of it or a close 'standard'relative and would also depend on the quality of the powder. Originally the overly hygroscopic powder was rather finely ground before mechanically mixing and tended not only to absorb moisture, but would rapidly separate if shaken during transport or storage. It also had a nasty habit of exploding and killing the mixers. Early Cannon masters on average were not old men as they had their own secret and personal recipes as to it's constituents and how to grind and mix the stuff. They learned not to use any iron/steel fittings, tool, nails, just brass or bronze, which is non-sparking. (felt slippers, as iron boot nails were also a no-no.)

Wet mixing and extrusion into known sized strings of known lengths along with sieving, corning, was not only more consistent, but less hygroscopic, and did not settle out. standardising the grains into the F system resulted in standard and consistent results. As did sealing it into tins rather than wood barrels. Even ww2 Iowa class battleships stored their bagged powder in non-sparking sealed tins in their magazines.

Now on to the mystery behind the letter 'F'. The letter 'F' stands for "Fine" and dates back to the time when the grains were designated F or C (for "coarse" grains). The number of times the letter F occurs in the powder grade shows the average size of the powder grains. The more times the letter F occurs in the name, the smaller the grains. What this means is that the size of "FFFg" grains are smaller than "FFg" grains, and "FFFFg" is even smaller than these two. When black powder is manufactured, the grains are sorted through sieves of standard sizes and classified that way.


Powder-Grade----Mesh-Size----Average-Size-in-mm.

Whaling------------4-mesh-------4.750-mm.-(0.187-in.)
Cannon-------------6-mesh-------3.35-mm.-(0.132-in.)
Saluting-(A-1)----10-mesh------2.0-mm.-(0.079-in.)
Fg-------------------12-mesh------1.7-mm.-(0.0661-in.)
FFg-----------------16-mesh------1.18-mm.-(0.0469-in.)
FFFg---------------20-mesh------0.85-mm.-(0.0331-in.)
FFFFg-------------40-mesh------0.47-mm.
FFFFFg-----------75-mesh------0.149-mm.

Note that the first 3 grades are intended for use with cannon. The A-1 grade is generally used for artillery blanks used for firing gun salutes. Fg is made for using in large bore rifles and shotguns (8-gauge and larger). FFg powder is used for historical small arms such as muskets, fusils, rifles and large pistols. FFFg powder is for smaller caliber rifles (below .45 caliber), pistols, cap-and-ball revolvers, derringers etc. FFFFg and FFFFFg are mostly used as priming powder for flintlocks. In the image above, the two grades of powder were intended to be used in a historical re-enactment and the FFg powder was meant for the main powder charge of a flintlock rifle, while the FFFFg powder was intended to be used in the pan of the flintlock as a priming powder.