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The Ultimate Reloading Manual
Wolfe Publishing Group
  • alliant reloading data
  • reloading brass
  • shotshell reloading
The Ultimate Reloading Manual
load development

Modern Handloads for the Classic .218 Mashburn Bee

Author: Patrick Meitin
Date: Nov 15 2022

The .218 Mashburn Bee test rifle was a Birmingham Small Arms (BSA) Martini single shot rebarreled with a heavy, 26-inch barrel and furnished with a gorgeous walnut forearm and buttstock.

The .218 Mashburn Bee is an “improved” version of the standard .218 Bee cartridge, including less case taper, lengthened chamber, sharper shoulder and shorter neck. These features increase velocity to the tune of 10 to 15 percent. Art Mashburn, a respected Oklahoma City gunsmith and owner of Mashburn Arms & Sporting Goods from 1941 to 1972, created the Mashburn Bee. Mashburn cases are fireformed from .218 Bee cartridges fired in a .218 Mashburn Bee chamber. Using fresh, factory ammunition or handloading new brass before fireforming minimizes shoulder and neck splits, though annealing older cases also does the trick. Factory .218 Bee ammunition and handloading cases are available from Hornady and Winchester, with Hornady seemingly the more reliable source today. Fireformed Winchester cases held about 17.1 grains of water filled to the brim, Hornady cases 19.2 grains. Mashburn case length matches the .218 Bee, at 1.340 inches. After fireforming you will likely find cases a touch short, but not to worry, they will function just fine.

Shown for comparison from left to right are; the .22 K-Hornet, Winchester .218 Bee, .218 Mashburn Bee and .221 Remington Fireball.

Load data for the .218 Mashburn Bee can prove scarce, with recipes including newer powders essentially nonexistent. Yet, .218 Bee data is commonly available. My basic approach was to begin with published .218 Bee data, creating my ladder chart, then adding 10 percent to each charge. Powders such as Alliant 2400, Hodgdon H-4198 and H-110 and IMR-4227 commonly appear in Bee data, while I added Vihtavuori N110 and N120, Hodgdon Lil’Gun and CFE BLK, Accurate 1680, Alliant Reloder 7 and Shooters World Blackout. For dependable temperature stability, I favor powders like H-4198 (a Hodgdon Extreme Series powder), CFE BLK (including a copper fouling eraser), the Vihtavuori formulas and Accurate 1680. Blackout charges were extrapolated from previous work conducted with the .218 Bee and that data was extrapolated from .300 Blackout/Accurate 1680 data.

Bullets used to test the .218 Mashburn Bee include, left to right,
Midsouth Shooters Supply 34-grain Varmint Nightmare,
Speer 40-grain Varmint Spire SP, Berger 40-grain Flat Base Varmint,
Sierra 45-grain Varminter Hornet SP and Hornady 50-grain Varmint SP SX.

While the Birmingham Small Arms Company (BSA) Martini test rifle certainly has a stout, and reliably safe single-shot action, their extractors are notoriously weak. This leads to sticky cases while shooting maximum loads. For this reason, listed powder charges remain conservative, with a few exceptions. Most of these loads could no doubt be pushed a bit farther from a solid bolt action – perhaps even this single shot – though I still encourage starting with the listed start loads and working upwards, while watching carefully for pressure signs. Remember, chamber dimensions can differ slightly in older wildcats such as the Mashburn Bee, resulting in wildly disparate chamber pressures.

The .218 Mashburn Bee test rifle was shot atop a sturdy
portable bench, supported by an MTM Case-Gard K-Zone Shooting Rest.

The British Empire made these rifles by the millions, and they were

The tightest group assembled with the 34-grain
Midsouth Shooters Supply Varmint
Nightmare bullet measured .93 inch
at 2,742 fps, using 13 grains of IMR-4227.

even used as reserve weapons in various colonies into World War II. This Martini was rebarreled with a heavy 26-inch barrel (.83 inch at muzzle) with, as best I can determine, a 1:14 rifling twist. The forearm and buttstock were created from fine, checkered walnut, with a thin rubber buttplate to provide an average 13½-inch length of pull. The forearm was carved wide to sit well on a rest, and the butt included a high, rollover comb. The trigger broke at crisp 1.75 pounds. A Hi-Lux SPG416x44MD (4-16x 44mm) scope mounted on a one-piece Weaver base was used during testing. The finished weight was 14 pounds.

I have shot many rebarreled Martinis, most relinquishing respectable varmint-grade accuracy. This, unfortunately, was not one of them. The rifle struggled to break an inch in most cases, with 1.5-inch groups deemed acceptable in this round of testing.

The tightest group of the entire Mashburn Bee test measured
.44 inch at 2,977 fps, using 16.5 grains of Alliant Reloder 7.

Cases were formed from WW-Winchester brass, and Winchester WSR primers were seated. Dies came from C-H Tool & Die/4-D Custom Die Company and an Area 419 ZERO Reloading Press was used to press all loads. All powder charges were carefully trickled onto a RCBS beam scale for maximum uniformity.

Bullets were chosen for small-varmint hunting, starting with Midsouth Shooters Supply 34-grain Varmint Nightmare and moving to Speer’s 40-grain Varmint Spire Soft Point, Berger’s 40-grain Flat Base Varmint, Sierra’s 45-grain Varminter Hornet and Hornady’s 50-grain SP SX (Soft Point, Super eXplosive). Ballistic coefficients are irreverent, as these squat bullets were designed to provide dismantling impacts on burrowing rodents at the velocities generated by this class of cartridge and its 250-yard maximum range.

The 34-grain Varmint Nightmare was selected as a short-range option to use in settled areas where ricochets might prove disastrous. They include a flatnose hollowpoint tip and are quite explosive on small varmints even from my .22 Hornet Taurus raging Hornet revolver. This bullet was paired with Vihtavuori and Hodgdon H-110 and IMR-4227, averaging a disappointing overall group size of 1.88 inch. All loads are loaded quite conservatively, as I viewed this as a short-range bullet. Vihtavuori’s N110 did best with a “maximum” load of 11 grains, printed 1.21 inches at 2,936 feet per second (fps), while H-110 did a little better with its 12-grain “start load,” printing 1.03 inches at 2,739 fps. IMR-4227 groups tightened with added powder, the “maximum” load of 13 grains produced the smallest group with this bullet; .93 inch at 2,742 fps.

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