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

.22 Hornet Fireformed Loads vs. .22 K-Hornet

Author: Patrick Meitin
Date: Jun 20 2022

The K-Hornet test rifle was built for varmint shooting using a Martini single shot action, 21½-inch heavy barrel and was restocked in gorgeous mesquite with rosewood forend and grip caps accented with maple spacers.

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.

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

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.

One of the better K-Hornet groups produced
during testing resulted from 12.5 grains of Alliant
Power Pro 300-MP and the 40-grain Hornady V-MAX.
That .34-inch group was sent at 3,095 fps.

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

Fifteen grains of Hodgdon CFE BLK produced this
.39-inch K-Hornet group by sending three Hornady
NTX lead-free bullets at an average 2,890 fps.

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.

Marks on the left side of the receiver show this Martini
action was once part of an Australian arsenal.
Many Martini rifles remained reserve weapons
into World War II across the English Empire.

 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.

Bullets used for testing included, left to right, Hornady’s 35-grain V-MAX,
Hornady’s 35-grain NTX, Speer’s 40-grain Varmint, Hornady’s 40-grain
V-MAX and Sierra’s 45-grain Soft Point Hornet.

Bullets chosen for testing were a mix of classic and modern options. I started with the squat Nosler 35-grain Ballistic Tip Varmint, followed by Hornady’s conspicuously longer 35-grain NTX lead-free bullet. In 40 grains, I chose Speer’s Varmint, which I would describe as a straight-walled, cone-ogive softpoint and finished with a Hornady V-MAX. Sierra’s 45-grain Varminter Hornet Soft Point is a classic bluntnosed softpoint.

 I’ve often read that fireformed loads can relinquish good accuracy. I remained skeptical, convinced this was another case of bad information formed decades ago and passed along as gospel forevermore. I decided to find out for myself. I obviously needed to fireform a bunch of .22 Hornet rounds to create needed K-Hornet cases, so decided to make something of the fireforming process. This also provided the opportunity to record the relative differences between the .22 Hornet and K-Hornet rounds while using identical powders, if not identical charge weights.

Vihtavuori’s N110 performed relatively poorly in this test,
the best K-Hornet group measured only .73 inch at just
2,769 fps using 11 grains of powder – it’s best showing.

 For both cartridges the 35-grain Nosler was paired with Alliant Power Pro 300-MP (a new Hornet powder for me), Hornady’s nontoxic 35-grain NTX with Hodgdon CFE BLK, the Speer with Vihtavuori N110, the 40-grain V-MAX with Hodgdon Lil’Gun, and the 45-grain Sierra with Accurate 1680. All loads were carefully measured on an RCBS balance scale, as the smallest deviations in powder charges with cartridges this small negatively affect accuracy. The .22 Hornet rounds used from 9 (start loads) to 13 grains (maximum loads) of powder, the K-Hornet loads from 10 to 15.5 grains. The Remington brass already mentioned was used throughout, as were Federal Ammunition No. 205 Small Rifle primers. Full-length die sets were used from Hornady (.22 Hornet) and C-H Tool & Die and 4-D Custom Die Company (.22 K-Hornet), both screwed into an Area 419 ZERO Reloading Press. The K-Hornet sizing die was backed off to allow neck-sizing only during loading.

Any skepticism regarding fireforming accuracy quickly evaporated as groups began to assemble. It didn’t seem possible, but the fireforming loads produced many sub-half-inch groups. The 35-grain Nosler printed .46 inch at 2,920 fps over 11.5 grains of Alliant Power Pro 300-MP. Hornady’s 35-grain NTX seated over 12 grains of Hodgdon CFE BLK assembled a .38-inch group at 2,249 fps. With Hodgdon Lil’Gun and Hornady’s V-MAX, .57- and .59-inch groups resulted from 12- and 13-grain loads, with velocities of 3,036 and 3,062 fps, respectively. Accurate A-1680 provided better accuracy, producing .39-, .37- and .29-inch groups at velocities from 2,283 to 2,422 fps. What CFE BLK and A-1680 lacked in velocity, they made up for in accuracy, while Power Pro 300-MP and Lil’Gun were tops for velocity. Unfortunately, Vihtavuori’s N110 failed to impress all-around in this session of testing.

This performance created apprehensions that K-Hornet loads would fail to match the accuracy of the fireform loads. I mean, how ridiculous would it be to own a rifle that must be fed fireforming loads to provide its best accuracy?

 I needn’t have worried, though fireforming loads did beat K-Hornet accuracy on several occasions. What was striking was the substantial gains in velocity. Nosler’s 35-grain Ballistic Tip Varmint shot a .36-inch group with 12 grains of Alliant Power Pro 300-MP, hitting 3,017 fps, for a 250 fps gain in velocity over the .22 Hornet. Hodgdon’s CFE BLK combined with the Hornady NTX boosted velocity even further, a 512 fps margin with its most accurate load of 15 grains of powder at 2,890 fps. That group measured .39 inch. Vihtavuori N110 Sierra 40-grain Hornet performed a touch better from the K-Hornet, the best group was .73 inch at 2,769 fps, adding 188 fps to velocity. The Lil’Gun V-MAX combination proved worthwhile, resulting in a .58-inch group at 3,338 fps and providing a 298 fps advantage over the standard Hornet load. Accurate 1680 is the one area where fireforming loads assembled better overall group averages, though 12.5 grains of A-1680 at 2,567 fps (284 fps faster than the .22 Hornet) produced this test’s tightest group, at .28 inch.

Acquiring a fresh box of Hornady 40-grain V-MAX as this test neared completion, I couldn’t leave well enough alone. This is my Hornet-class varmint bullet of choice, so I wanted to see how it paired with the K-Hornet powders I had the most of – Alliant Power Pro 300-MP, Hodgdon CFE BLK, Vihtavuori N110 and Accurate 1680. Picking a winner proved easy; 12.5 grains of Power Pro 300-MP printed .34 inch at a speedy 3,095 fps, and 15 grains of CFE BLK created a .58-inch group at 2,887 fps. Nothing else came close, as I’m guessing the slow rifling twist offered the long-for-weight V-MAX minimal stabilization at the slower velocities.

The CFE BLK 35-grain NTX and Power Pro 300-MP 40-grain V-MAX will become my loads of choice for this K-Hornet rifle. It is a cartridge I really look forward to shooting in the varmint fields near home.