| No. 1, .3 of an inch No. 2, .15 of an inch | } | Initial Velocity required, 1450 feet +50-50, for Rifle. |
| No. 2, .15 of an inch No. 3, .10 of an inch | } | Initial Velocity required, 1500 feet +50-50, for Cannon. |
| No. 4, .06 of an inch No. 5, .02 of an inch | } | Initial Velocity required, 1550 feet +50-50, for Musket. |
Rifle powder is used in the Parrott rifles of 8-inch, 100-pounder, and 60-pounder. Navy cannon powder in all other rifles and all smooth-bores.
131. Size of the grain is required to conform to the following:
| Pass through No. 1 Remain on No. 2 | } | all Rifle. |
| Pass through No. 2 Remain on No. 3 | } | all Cannon. |
| Pass through No. 4 Remain on No. 5 | } | all Musket. |
Ten per cent. variation tolerated.
132. Gravimetric Density, is the weight of a given measured quantity: it is usually expressed by the weight of a cubic foot in ounces.
This cannot be relied on for the true density, as the size and shape of the grain may make the denser powder seem the lighter.
Cannon powder should have a gravimetric density of about 875 oz., and not exceeding 900 oz., to the cubic foot. (It actually varies with different makers from 875 to 975.)
133. Specific Gravity.—The specific gravity of gunpowder is between 1.70 and 1.75.
All the powder of any lot being made of the same mill-cake, the specific gravities are equal although the gravimetric densities may vary.