Varmint Rifle - Calibers

Calibers

Since varmints are generally smaller animals, large, heavy bullets are not needed. A light, fast bullet gives a flat trajectory, making range estimation less vital for accurate shot placement. Velocities for modern varmint rounds are usually in excess of 3,000 ft/s (910 m/s) and some such as the .220 Swift and .204 Ruger can exceed 4,000 ft/s (1,200 m/s). This allows long range shots with a short time of flight, and little change in trajectory at different ranges (see external ballistics). A bullet drop of only a couple of inches (about 5 cm) is enough to cause a miss on smaller varmint animals; so flat trajectories increase hit probability at long ranges. Fast, lightly constructed bullets have additional advantages of rapidly disintegrating upon initial contact. Disintegration minimizes the range of ricochet particles; and energy release of disintegration kills small animals more quickly than a penetrating wound.

Rifles firing .22 caliber bullets became popular varmint guns after World War I. Calibers up to .264 caliber (6.5 mm), including .243 Winchester, 6mm Remington and .25-06 Remington, became popular for ranges over 200 meters (220 yards) as the ballistic advantages of heavier bullets were recognized. Varmint shooting is one of the few areas where calibers smaller than .22 (5.56 mm) are found; the .17 Remington and various other .17 caliber (4.5 mm) wildcats have a vocal following, and the new .204 Ruger is well suited to varminting, and may be the first in a new line of .20 caliber (5mm) rounds.

For shorter ranges (less than about 100 yards (100 meters)) rimfire cartridges such as .22 Magnum, .17 Hornady Magnum Rimfire, and .17 Mach 2 are popular. The .22 Long Rifle will also do, but the low muzzle velocities result in a supersonic to subsonic transition on the way to the target, which can negatively affect accuracy.