Range Certification
The Values given for each element of certification are the maximum permitted
Range |
Muzzle Velocity (feet per second) |
Muzzle Energy (pounds feet) |
50 Metre |
3500 |
5160 |
25 Metre |
1675 |
1476 |
Practical |
1675 |
1476 |
Calculating Muzzle Energy
Muzzle Velocity (MV); the speed that a bullet leaves the barrel, this should be measured on a chronograph because M/V will vary depending on barrel length using the same bullet. This is often given on the box for factory ammunition or in loading tables with the length of test barrel for hand loads.
Mass (M); the weight of the bullet head in grains will be on the box in factory ammunition or heads, if home cast the head should be weighed because weight can vary depending on the alloy used and sizing.
Constant (C); 450,400 - the number of grains in a pound of powder 7000 x 64.342 (gravity x 2)
The calculation is: ((MV x MV) x M) / C
Examples;
a 115 grain head at a Muzzle velocity of 1300 ft/sec will have a Muzzle energy of 431 lbs/ft and can be used on all of our ranges
((1300 x 1300 [ = 1690000]) x 115 [ = 194350000]) / 450400 = 431.50532
a 300 grain head at a Muzzle velocity of 1581 ft/sec will have a Muzzle energy of 1664 lbs/ft MV is ok but Muzzle Energy is too high to use on the 25 Metre or Practical Ranges - should only be used on the 50 Metre Range
((1581 x 1581 [ = 2499561]) x 300 [ = 749868300]) / 450400 = 1664.89409
a 215 grain head at a Muzzle velocity of 3400 ft/sec will have a Muzzle energy of 5518 lbs/ft MV is ok but Muzzle Energy is too high to use on any of our Ranges
((3400 x 3400 [ = 11560000]) x 215 [ = 2485400000]) / 450400 = 5518.20603