.22 Hornet Fireformed Loads vs. .22 K-Hornet
Date: Jun 20 2022
I’ve owned the same .22 Hornet rifle since 1982, a Savage Model 340-E that has now accounted for more burrowing rodents and called predators than I could possibly guess. More recently, I scored a sweet little .22 K-Hornet built around a Birmingham Small Arms Company (BSA) Martini single-shot action. The intriguing K-Hornet is the “improved” .22 Hornet developed by former Lyman employee, Lysle Kilbourn in 1940.
The K-Hornet offers a nearly nine percent improvement in case capacity over the older Hornet by reducing body taper from .010 to .012 inch and moving the 35- to 40-degree shoulder forward to shorten the neck. The new (current production) Remington .22 Hornet cases used for testing held an average of 14.3 grains of water, while fireformed K-Hornet cases from those brass held 15.5 grains. Most load data suggests 100 to 150 feet per second (fps) gains in velocity over the standard Hornet, though I did much better using modern propellants (see accompanying table). Perhaps more appealing, the K-Hornet’s improved case design provides more positive headspacing on the created shoulder instead of the rim, as occurs with the older Hornet. This helps to improve case life, but also lends the K-Hornet more reliable accuracy. The K-Hornet includes a maximum overall length of 1.75 inches, compared to the 1.723 inches of the .22 Hornet, at least while shooting classic bluntnosed Hornet bullets (more on this later).
Cases are created by simply shooting standard factory or handloaded .22 Hornet rounds in a K-Hornet chamber. If going the handloading route, loading new brass is generally recommended, though I used once-fired Remington .22 Hornet brass and lost just one case through 100 shots. I used budget-priced 40-grain softpoint bullets and a low-pressure load of Hodgdon H-4198 for fireforming. Fireforming also ensures cases are fitted to individual chambers, as several variations have appeared, including slightly differing rim-to-shoulder and shoulder-angle dimensions. The most common version includes 1.13-inch rim-to-shoulder specifications with a 35-degree shoulder. Dimensions falling under these numbers may require reducing maximum loads. This also makes neck sizing advised for top accuracy. Trim-to length is 1.39 inches.
The .22 K-Hornet used for testing is a stylish little single shot, measuring a trim 37 inches long and weighing a touch more than 9 pounds with the addition of a Bushnell Elite 4500 4X Multi-X 4-16x 50mm scope set in Weaver 4-hole rings. That mass comes mostly from
the heavy (.795 inch at the muzzle), 21½-inch barrel (1:16 twist). The rifle was professionally stocked in gorgeous mesquite with maple spacers between the main stock and rosewood back-slant forend and flared grip caps. The hand-checkering, slim-wrist, deep-top thumb groove, Monte Carlo-style comb and plain buttplate combine to create a comfortable fit. The BSA action is of the kind dominating the British Empire during the early 1900s, most commonly chambered in .303 British. This one is stamped “Commonwealth of Australia, 20063, N.S.W., 2508.” Martini rifles were common throughout “The Empire,” many of them sticking around as reserve rifles into World War II. I would wager, based on the markings noted, this was such a rifle.
I’ve shot a good number of these rebarreled Martinis, chambered in various varmint cartridges. They generally relinquish useable varmint accuracy, but with high-pressure cartridges the Martini’s weak extractor system can prove lacking with hotter loads. I avoid maximum loads in Martini rifles, especially if they will be shot in warm conditions common to varmint fields. During this project, that issue arose only while using published Hodgdon Lil’Gun maximum loads; accompanying loads ejected slickly.
With the Hornets, there are pros and cons to both classic bluntnose Hornet bullets and modern polymer-tipped examples. The thin-skinned classics (and 35-grain polymer-tipped numbers) provide explosive expansion at Hornet velocities, which also helps eliminate ricochets while shooting in settled areas. The shortfalls of lighter/blunted Hornet bullets are the stumpy profiles, which also mean poor ballistic coefficients (BC) and steeper drops at ranges beyond 200 yards. If inclined to take longer shots, sleeker poly-tipped bullets will provide added reach. For instance, shooting something like a 40-grain Hornady V-MAX bullet allows me to confidently extend my Hornet’s effective range to 300 yards through 9 to 11 inches less drop when compared to either a 35-grain V-MAX/Nosler Ballistic Tip Varmint or standard-issue 45-grain Hornet softpoint. This is all due to superior BCs, flatter trajectory and minimized wind drift.