.256 Winchester Magnum Pistol Handloads
Date: Feb 10 2021
After conducting a .256 Winchester Magnum load test for Varmint Rifles & Cartridges (Fall 2020) involving a converted Martini rifle, the opportunity to purchase a 10-inch Thompson/Center (T/C) Contender pistol barrel so chambered proved irresistible. The .256 Winchester Magnum was created by necking down the .357 Magnum. This is where the magnum comes from, as the round hardly warrants magnum status. The .256 betters the ancient .25-20 Winchester by about 500 feet per second (fps) with same bullet weights, holding an additional 4.5 grains of water. As a small-game handgun cartridge, the .256 offers tame muzzle report and recoil, and good long-range pistol ballistics.
It’s fitting to revisit the .256 Winchester Magnum as a pistol project, as the cartridge was handgun inspired in response to Remington’s .22 Jet and initially released in Ruger’s Hawkeye single-shot pistol in 1961. Marlin chambered the cartridge in the Model 62 Levermatic lever rifle a year later. Neither of those firearms caught on, causing the cartridge to quickly fade. Ruger Hawkeye pistols are now collectors’ pieces, though Merrill and perhaps E. A. Brown single-shot pistols, and especially T/C Contender barrels, are still commonly encountered.
I’ve remained an enduring T/C Contender fan, owning a couple actions and numerous barrels chambered in anything from varmint rounds to larger big-game cartridges. The design is stout, reliable and typically accurate, so adding a .256 Winchester Magnum barrel to my T/C lineup was exciting. An original T/C scope base was added, and an older Leupold M8-2x pistol scope was mounted.
A 10-inch Contender barrel gives up an average 500-600 fps to a rifle chambered in the .256 Winchester Magnum. This leads to bullet expansion concerns, if the cartridge is to be used as a small-varmint round, as I intended. Bullets were chosen accordingly. As a varmint round, I see Hornady’s 60-grain FP (flat point) as most promising, with GT Bullet’s 55-grain cast-lead hollowpoint a viable short-range option. Such bullets were designed for .25-20 leverguns with tubular magazines, assuring reliable expansion when pushed to only 1,800-2,200 fps.
Sierra’s 70-grain BlitzKing – the lightest polymer-tipped .257 bullet available – provided limited small-varmint expansion even from the .256 rifle (though fine accuracy), Hornady’s 75-grain V-MAX did a better job of opening up ground squirrels. I included both, as they provide an ideal solution while predator calling, inflicting minimal pelt damage and extending range via superior ballistic coefficients.
I chose as many viable powders as possible, though I did eliminate a few I deemed unduly dirty or prone to pressure spikes under a hot sun. Alliant 2400 relinquishes excellent velocity (and accuracy), but was left out as pressure tends to mount quickly, which makes me nervous with a combination of maximum loads and warm varmint-season weather. That leaves Hodgdon H-110, H-4198 and CFE BLK, IMR-4227 and Accurate A-1680, A-2015 and A-5744.
One hundred cases were secured from Quality Cartridge, top drawer brass with proper headstamps. Cases were also formed from new Starline .357 Magnum brass, to help provide a more accurate accounting of that multistep, labor-intensive process. New or carefully-annealed .357 Magnum brass are run through a Redding Form Die No. 1, creating a small shoulder and mouth of roughly a .35 caliber. These are then run through Redding’s Form Die No. 2, taking neck diameter down to about .30 caliber. Next, a Redding .256 Form and Trim Die is used to further reduce neck diameter; a file applied to remove any protruding material before chamfering to remove burrs, and finally, a full-length die is used to finish.
When setting up the form and trim die, I failed to consider the further case lengthening that would occur during final sizing with a Redding Series B .256 Winchester Magnum full- length die. This required still more length trimming and tedious chamfering, which inspired the purchase of a Little Crow Gunworks Ultimate Trim Tool to speed up the process.
Lesson One: invest in enough experimentation to set up the form and trim die to remove enough length that brass emerges at the proper specifications (trim-to length 1.271 inches), avoiding the second trimming/chamfering. Lesson Two: after final full-length sizing, and trimming with the Little Crow trimmer, latching the T/C action on those cases required some force. A return to the full-length die, adjusting it until the shellholder touched the die head and then adding another quarter turn to create an over-camming effect to set shoulders back further solved the problem. Still another trim was required. Final Lesson: if your time is worth anything, the $48.50 per 50 for ready-to-load Quality Cartridge brass is a bargain!
If creating .256 cases from .357 brass, new cases are best to start, and the multistep form dies are worth the investment and added steps. Of 250 fresh Starline .357 Magnum brass formed there was not one split or wrinkled neck. Avoid nickel-plated brass, as they flake and peel given this degree of resizing. Check neck thicknesses carefully after resizing to assure there is enough room remaining for expansion and bullet release during ignition, turning or reaming as required to assure dangerous pressure spikes do not occur. A good baseline is .015- to .016-inch thick. Weighing water capacity between .256 cases formed from Starline, Winchester, Remington and Federal .357 Magnum brass – and the Quality Cartridge cases – showed surprising uniformity. All held about 22.5 grains of water when filled – give or take a tenth of a grain. CCI 400 Small Rifle primers were seated. Brass was alternated between powders to give the Quality Cartridge and reformed Starline cases equal time. Listed loads start with Quality Cartridge brass.