These tables were calculated by computer.  A standard scientific technique was used to predict trajectories from the best available data for each round.  Trajectories shown typify the ammunition's performance at sea level, but note that they may vary due to atmospheric conditions and the equipment.

     

All velocity and energy figures in these charts have been derived by using test barrels of indicated length.

     

Ballistics shown are for 24" barrels, except those for .30 Carbine and .44 Remington Magnum, which are for 20" barrels.  These barrel lengths were chosen as representative, as it's impractical to show performance figures for all barrel lengths.

     

The muzzle velocities, muzzle energies and trajectory data in these tables represent the approximate performance expected of each specified loading.  Differences in barrel lengths, internal firearm dimensions, temperature, and test procedure can produce actual velocities that vary from those given here.
 
CENTERFIRE  RIFLE  VELOCITY  VS.  BARREL  LENGTH
Muzzle Velocity Range (ft./sec.) Approx. Change in Muzzle Velocity per 1" Change in Barrel Length (ft./sec.)
2000-2500 10
2500-3000 20
3000-3500 30
3500-4000 40

1.  Determine how much shorter, or longer, your barrel is than the test barrel.

 

2.  In the left column of the above table, select the muzzle-velocity class of

     your cartridge.

 

3.  To the right of that class, read the approximate change in velocity per   

     inch of barrel length.

 

4.  Multiply this number by the difference in the length of your barrel from 

     that of the test barrel.

 

5.  If your barrel is shorter that the test barrel, subtract this figure from the

     muzzle velocity shown for your cartridge.

 

6.  If your barrel is longer, add this figure to the muzzle velocity shown.

 
The trajectory figures shown in these ballistics tables are the rise or drop, in inches, of the bullet from a direct line of sight at selected yardage.  Sighting-in distances have been set at 100 to 250 yards.

     

The line of sight used is 1 1/2" above the axis of the bore.  Since the rise or drop figures shown at the stated yardage are points of impact, you must hold low for positive figures, high for negative figures.

 

Many shooters who use the same cartridge often, find it helpful to commit the rise and drop figures for that cartridge to memory, or tape them to their rifle stock.  That way, they know instantly the right "hold" as soon as they estimate the target's range.

 

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