“bore diameter”

If you’re a fan of the quarter-bores, the .257 Weatherby Magnum will perform above and beyond what you’d normally expect from this bore diameter.

Introduced in 2008, the .416 Ruger is the only commercially produced cartridge in that .416-inch bore diameter designed to fit in a long-action receiver, making it an ideal choice for dangerous game.

The 6.5mm craze shows no signs of slowing down; in fact, it’s looking to be the bore diameter of the 21st century. Which of these two new cartridges is the better choice for the hunter? Contributor Philip Massaro examines the pros and cons of each.

While there may be a shine on some of the modern releases in the 6.5mm bore diameter, the 6.5x55 Swedish still makes a sound choice for the practical hunter due to its combination of terminal ballistics, flat trajectory and minimal recoil.

The all-new 6.8 Western brings the .277-inch bore diameter to life in a cartridge with a muzzle velocity that won’t burn up a throat prematurely, and offers the heavier, higher BC bullets that have been so popular among long-range shooters and hunters.

Metric cartridges have traditionally struggled in America, but even in the 1950s, the engineers at Winchester saw the benefits of the 6.5mm bore diameter. The 1958 release of the .264 Winchester Magnum in the Model 70 Westerner rifle saw a flat-shooting, hard-hitting voluminous case, perfect for medium-sized game.

Loosely based on a shortened .404 Jeffery case with the rim rebated to the .535-inch case head of the H&H family, the .270 WSM was the third commercial cartridge using the .277-inch bore diameter, and betters the velocity of the .270 Winchester by 200 to 250 fps.

Not all magnum cartridges bear the name, but still meet all the criteria for the title. Here’s a look at five of the best.

Between the .270 Winchester and the .270 WSM, which offers the best performance for hunters? Contributor Philip Massaro compares the two and picks the winner.