We've all seen it: as soon as a new cartridge becomes popular, experimenters start modifying the cartridge case to come up with new variations. These mods usually involve either increasing or decreasing bullet diameter, with perhaps some minor modifications to shoulder angle or case length. One of the most popular cartridges for modification has been the classic .308 Winchester, which, by my count, has spawned five "children" that have gone on to become legitimate factory offerings.
The .308 Winchester began as a US government project to replace the .30-06 Government cartridge, which it eventually did, but it was labeled as the 7.62x51mm NATO. In a strange twist, Winchester offered it as a civilian chambering in 1952, two years before the government specs were nailed down and adopted. It became widely popular both as a military and civilian round because it offered an excellent balance of accuracy and power, earning the coveted label of being an inherently accurate cartridge. A typical loading launches a 165-grain bullet at 2700 fps.

Just three years after the .308's release, Winchester followed up with the .243 WIN, made by simply necking down the .308 to take 6mm bullets. It quickly found a niche among hunters who wanted a light-recoiling rifle that could serve dual duty as both a varmint and a deer cartridge. It also proved capable of excellent accuracy, but with nowhere near the long barrel life that characterized the .308. A do-it-all loading drives a 95-grain bullet at about 2960 fps.

While the 6.5mm bore size has long been popular in Europe, it struggled in North America until the introduction of the 6.5 Creedmoor. However, long before the Creedmoor skyrocketed to popularity, there was the .260 Remington, a 6.5mm bore size that closely duplicates Creedmoor performance. As the name suggests, it was introduced by Remington, first appearing under their name in 1997. It had existed before as the 6.5-08 A-Square, but it took Remington to bring it to some level of popularity. Shooters can expect about 2840 fps from a typical 130-grain bullet.

The 7mm-08 dispensed with the imperial caliber designations and went straight to metric using .284-inch bullets. Wildcats with this bore size appeared way back in the 1950s, but it took Remington to standardize it in the 1980s. It found a lot of life with rifle shooters competing in the metallic silhouette game back then, as it had the right combination of power and mild recoil to take down heavy rams at 500 meters. Of course, it was no slouch in downing big game either. With the ability to drive a 140-grain bullet at about 2860 fps, it's a capable cartridge.

Introduced in 2006, the .338 Federal is the most recent cartridge derived from the .308 WIN. It was a joint project between Federal Ammunition and Sako, the famous Finnish rifle manufacturer. It also has the honor of being the first cartridge designed by Federal and bearing their name. It has had only limited commercial success, although it is no doubt an effective hunting round to moderate distances. Federal is the only company currently loading this cartridge, with their recipe featuring a 200-grain bullet that leaves the muzzle at 2700 fps.
The .358 Winchester is the largest bore size parented by the .308 WIN in commercially available ammunition. There were, of course, numerous wildcat cartridges developed by dedicated hobbyists, but the .358 WIN remains the largest-bore size that factories load for. It was introduced at almost the same time as the .243 WIN in an effort to win over fans of big bullets. It met with immediate success but began to fade as consumers became enamored with high-velocity cartridges. Shooters who want to try it will have to search used gun racks. I've often thought it might be a cartridge worth experimenting with .38 Special handgun bullets loaded light. As for factory ammo, Hornady's loading for this cartridge drives a 200-grain bullet at about 2475 fps.

If imitation is the sincerest form of flattery, then the .308 WIN should indeed be flattered. Having spawned five "children," it's easy to say the old war horse deserves its place in the cartridge hall of fame. The similarity in cartridge head size and magazine interchangeability among its children make any of these cartridges an easy choice for a custom build, offering an easy caliber swap in the future.
Al Voth calls himself a "student of the gun." Retired from a 35-year career in law enforcement, including nine years on an Emergency Response Team, he now works as an editor, freelance writer, and photographer, in addition to keeping active as a consultant in the field he most recently left behind—forensic firearm examination. He is a court-qualified expert in that forensic discipline, having worked in that capacity in three countries. These days, when he's not working, you'll likely find him hunting varmints and predators (the 4-legged variety).