Bullets: What’s the Difference?

SINCE THE INVENTION of gunpowder, firearms evolution has forced bullet designers to keep pace with a long progression of changing requirements. The manifold differences in today’s comprehensive range of sporting bullets can be perplexing. This is an attempt to explain these properties without venturing into ballistic theory.

With the exception of bullets used in muzzle-loaders and some early breech-loaders, all are required to have a slightly larger diameter than the relative firearm’s bore-diameter, to provide sufficient material for the rifling lands to bite into. The difference in diameters is usually within four to eight thousandths of an inch, but this is not a convention. The 7.62x39mm Soviet M43 bullet can be as much as twelve thousandths of an inch over the 7.62mm (0.3ꞌꞌ) bore size. Using surplus bullets recovered from old M43 ammunition could result in catastrophic failures in other barrels. Bullet and bore dimensions led to frequent misnaming of cartridges. For example, .308 Winchester and .300 Winchester Magnum cartridges both require 0.308ꞌꞌ bullets. The .300 describes the bore diameter, not the bullet diameter. This binomial problem caused much regrettable disorder in the naming of British