The Staying Power of the .257 Roberts Cartridge

The .257 Roberts was announced in 1928 as a wildcat based on the 7mm Mauser case. The “quarter-bore” was fashionable due to fine game performance demonstrated by the .250 Savage. The wildcat became the “.25 Roberts,” honoring its lead developer, Maj. Ned H. Roberts, a well-known outdoor writer and experimenter.

The final form of the .25 Roberts was only slightly changed from the 7mm Mauser. In addition to a smaller neck, the wildcat had a shallower 15-degree shoulder angle and a slightly shorter case. It did not take long for custom riflemakers to begin building .25 Roberts rifles. Then, in 1934, Remington took interest.

Remington’s .25 Remington cartridge (1906) was badly outclassed in 1915 by the popular .250 Savage. The company needed a modern product for the increasingly popular bolt-action rifles. Remington cataloged the “.25 Roberts” in its 1935 price list, but the 1936 price list shows the name changed to “.257 Remington-Roberts.” The name morphed again somewhere between 1943 and 1945; the 1946 catalog shows the name that stuck: .257 Roberts.

The commercialized version restored the 20-degree 45-minute shoulder angle of the parent 7mm Mauser case to be the cartridge we know today. Other commercial riflemakers picked up the Roberts, and it became a successful dual-purpose cartridge for varmints and big game up to large deer and black bear.

The early Roberts exceeded velocities of the .250 Savage by roughly 200 fps. It even gave the proprietary .25 Niedner, which eventually became the .25-06 Remington, good reason to sweat. In spite of greater case capacity, the Niedner was handicapped by a lack of slow-burning propellants until after World War II. One account of the .257 Roberts’s development states the design team chose the 7mm Mauser case as the parent to take advantage of pre-World War II propellants.

Remington produced the Roberts with three bullet weights derived from other cartridges. The 87-grain and 100-grain loads were influenced by the .250 Savage, and the 117-grain load reflected the old .25-35 Winchester and .25 Remington cartridges. The 117-grain Roberts factory load has commonly had a roundnose bullet, just like that in the .25-35.

Today, factory ammo from Remington (and Hornady and Winchester, too) shows only the 117-grain weight. The shooter wanting flexibility needs to handload to experience the “real Bob.”

The Roberts experienced a unique transformation in 1974. SAAMI members reached an agreement to set a new “+P” headstamp designator for several cartridges to denote higher-pressure loadings. The .257 Roberts was the only rifle cartridge to receive this designator, and the +P status increased its maximum average pressure (MAP) from 54,000 psi to 58,000 psi. For comparison, the .30-06 has a MAP of 60,000 psi. Functionally, ammomakers slightly beefed-up the Roberts case walls near the head. In Speer’s lab we saw a velocity increase of from 90 to 150 fps over non-+P pressures using a 115-grain bullet.

Why was the Roberts originally “loaded down” to .250 Savage pressures? That’s tough to answer. Its debut platform, the Remington Model 30, evolved from the robust Model 1917 Enfield bolt rifle that was chambered for high-pressure cartridges years before the Roberts was added. Later, the slide-action Remington 760 was chambered for .257 Roberts, but also for other cartridges achieving or exceeding .30-06 pressures.

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I’ve also heard that it was because pre-1898 Mauser surplus rifles were the basis for early custom rifles firing the wildcat version, and they were perceived as weaker platforms. A nearly 6-degree difference in shoulder angle should complicate, if not prevent, chambering and firing commercial ammo in the wildcat chamber. Maybe it was concern over chamber variations in custom guns. All I can say is that granting “Bob” +P status in 1974 was a great kindness.

For a performance comparison, let’s put current .257 Roberts +P handloads next to its more modern challenger, the .25-06 Remington (1969).

Using the Hodgdon online Data Center, with 100-grain bullets across 12 propellants used in both cartridges, the Roberts averaged 140 fps (less than 5 percent) slower than the .25-06. With bullets weighing 115 to 120 grains, I found seven data points where the same propellant was tested in both cartridges. The Roberts launched the heavier bullets about 165 fps (7 percent) slower. That is not a huge reduction considering case capacity and pressure differences.

Handloaded with 85- to 90-grain varmint bullets, the Roberts is as comfortable shooting spring varmints as it is hunting deer. Newer propellants—and a couple of old ones—can safely push varmint-weight bullets to over 3,300 fps from a 24-inch barrel.

In the last few decades of the 20th century, a reintroduction of .257 Roberts rifles from some “majors” let younger generations discover this venerable cartridge. Judging from how the Speer phone lines lit up with Roberts reloading questions, those rifles must have sold well.

The Roberts offers no real handloading challenges. Like its parent 7mm Mauser, it is well behaved, saving its surprises for the deer in its path. Handloaders can load the full gamut of bullet weights enjoyed by early factory ammunition. Modern .25-caliber 100-grain hunting bullets are a great choice. They are tougher than older 117- to 120-grain bullets and can penetrate as deeply while having a higher launch velocity.

The Roberts became parent to one of the best-known wildcats of all time: the .257 Roberts Ackley Improved. I knew several people in the Dallas area who proclaimed the .257 Improved the perfect Texas deer cartridge.

The popularity and dual-purpose nature of the .250 Savage and the .257 Roberts were usurped in 1955 by the .243 Winchester and the .244 Remington (later renamed 6mm Remington). Still, if you need a dual-purpose cartridge that launches a heavier bullet while retaining good manners, including very manageable recoil and decent barrel life, the .257 Roberts is still a runner in my book.