5. Ballistics – velocities and energies

Striking velocities

The ‘observed velocity’ of shotgun ammunition is the average velocity of the shot charge over the first 20 yards of flight. An observed velocity of 1070 feet/second is approximately equal to a muzzle velocity of 1320 feet/second.

Using the Eley ‘standard’ cartridge (e.g. Grand Prix) with an observed velocity of 325 m/s (1070 f/s), the striking velocities are given below. The Eley ‘high velocity’ cartridges are approximately 5-10% faster but the difference at normal shooting distances is, in fact, negligible.

Table 13: Striking velocities in metres/second for Eley standard velocity cartridges

NOTE: To convert metres to yards, multiply by 1.09361. I do not have the data for yards and foot-pounds. Any offers?

Striking energy of shot

Kinetic energy is calculated from the pellet’s mass and velocity, and expressed here in foot-pounds. The striking energies of individual shot with an observed velocity of 1070 feet/second (muzzle velocity of 1350f/s) are given in Table 14 below.

Table 14: Striking energies in foot-pounds for individual shot (source: GT)

NOTE: To convert foot-pounds to joules, multiply by 1.3558. I do not have the data for metres and joules. Any offers?

Eley indicate that the minimum requirements for a clean kill on certain types of bird are:

• small birds e.g. snipe – 2 pellets each having striking energy of at least 0.5 ft-lb
• medium birds e.g. grouse – 3 pellets each having striking energy of at least 0.85 ft-lb
• large birds e.g. goose – 4 pellets each having a striking energy of at least 1.5 ft-lb.

Therefore, from Table 14 we can select the appropriate size of shot for the quarry at the distance at which we expect to shoot. We then need to consider the density of pattern thrown by our gun-ammunition combination to determine at what distances we can realistically shoot that quarry. This has already been done for us.

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