Wildcat Cartridges

I doubt if any cartridge has been “improved” by more people than the mild-mannered little 22 Hornet. From a technical point of view, improved versions of the 22 Hornet existed prior to the introduction of the cartridge by Winchester in 1932. To understand how that could have happened, we will have to turn back the calendar to the 1920s when various gunsmiths began searching for ways to improve the performance of an old black-powder cartridge called the 22 WCF or 22-15-45 Winchester when it was introduced in 1890. One of those gunsmiths was Adolph Niedner whose 1920s 25-caliber wildcat on the 30-06 Springfield case went on to be domesticated by Remington in 1969 as the 25-06 Remington.

The 22 WCF stayed in production until 1935 and when Winchester decided to introduce a “new” varmint cartridge in 1930. The headstamp on 22 WCF cases was changed to read “22 Hornet.” The 22 Hornet case was eventually beefed up a bit to strengthen it and due to the reduction in capacity, some of the early load data is excessive for today’s cases. The first rifle offered by Winchester in 22 Hornet was the Model 54 and when it was improved and reintroduced in 1937 as the Model 70, the 22 Hornet was among its options as well.

While many gunsmiths had their versions of the 22 Hornet improved, the 22 K-Hornet, introduced by Lysle D. Kilbourn around 1940, is the best known. At the time, Kilbourn worked for Lyman and among other duties, he was involved in publishing the company’s reloading handbook. He also did a bit of writing and articles written by him on the 22 K-Hornet ran in several publications, including the American Rifleman. Kilbourn picked up extra dollars by rechambering hundreds of rifles in 22 Hornet for his cartridge. I have seen only one and it was in a Winchester collection. A Model 70, it had “Kilbourn” stamped beneath “22 Hornet” on its barrel. Since it has always been a wildcat, case dimensions were never carved into stone and this may explain why the dimensions and shoulder angles of cartridge drawings shown in various reloading manuals differ.

There is one other thing. Once Kilbourn’s wildcat became widely known, some gunsmiths would stamp “22 K-Hornet” on the barrels of rifles they built, even though the case dimensions of their version of the 22 Hornet improved might differ. So regardless of what is stamped on the barrel of a rifle purchased at a gun show or elsewhere, if it does not come with reloading dies, the best bet is to fire a few rounds of 22 Hornet factory ammunition in the rifle and send the fired cases to Redding, Hornady, RCBS or Whidden Gun Works for a custom die set.

The amount of velocity gained by improving a cartridge depends on the powder capacity gained and it varies considerably with differences in case taper. The 22 Hornet case has an abundance of taper and fireforming it to an improved shape makes room for a bit more powder for higher velocities. Water capacity gain with an improved shape will vary among different brands of 22 Hornet cases, but it is usually less than 10 percent. The Winchester 22 Hornet cases I have average 54.7 grains in weight and have an average gross water capacity of 14 grains. When blown-out to the improved shape for my Winchester Model 70, capacity increased to 15.3 grains for a nine percent gain. Now, how does that translate to velocity gain?

The amount of velocity gained by improving the 22 Hornet case has long been debated and sometimes exaggerated, but the eventual publication of pressure-tested load data settled most of the arguments. About 20 years ago, Hodgdon ran velocity tests for the 22 Hornet and 22 K-Hornet in 24-inch pressure barrels. Winchester cases and WSR primers were used in both. The maximum velocities for the Hornady 35-grain V-MAX were 3,060 feet per second (fps) in the 22 Hornet and 3,137 fps in the 22 K-Hornet, although chamber pressure for the latter was 4,100 CUP higher. Moving to a 40-grain bullet, maximum velocities were 2,826 fps for the 22 Hornet and 3,045 fps for a 219 fps gain with the improved version, the latter at 16,600 CUP higher chamber pressure. While the 22 K-Hornet was 100 to 200 fps faster, the race would have been much closer if both had been loaded closer to the same chamber pressures.

A better comparison is in the 11th edition of Hornady’s Handbook of Cartridge Reloading. The maximum velocities with the 35-grain V-MAX were 3,100 fps for the 22 Hornet and 3,200 fps for the 22 K-Hornet. Respective maximums for the 40-grain V-MAX were 2,900 fps and 3,100 fps. As in the Hodgdon tests, velocity gain increased as bullet weight increased, which is good because I consider 40 grains to be the optimum weight for a bullet in either cartridge. But to be fair and balanced, I must add that barrel lengths used by Hornady were 22 inches for the 22 Hornet and 24 inches for the 22 K-Hornet and that may account for 40 to 50 fps of the velocity advantage shown for the improved version.

The 22 Hornet case is easily fireformed to the improved shape. Ron Reiber, who was the lead ballistician at Hodgdon for many years, mentioned to me that prior to fireforming any cartridge case to the improved shape, he always applied a light coat of Hornady One-Shot spray lube. It is a method I have since used when forming 22 Hornet Improved cases and doing so virtually eliminates case loss.

As a rule, relatively short bullets such as the Hornady 35-grain V-MAX and those of softnose design with a maximum weight of 40 grains are the best choices for rifles in 22 Hornet and 22 Hornet Improved. Shooting longer bullets such as the Hornady 40-grain V-MAX and Nosler Ballistic Tip of the same weight is tempting, but they are too long to be completely stabilized by the 1:16 twist of most rifles. Also, seating them with their ogive beyond the mouth of a case results in an overall cartridge length too long for the magazines of most Hornet rifles.

Improved versions of the 22 Hornet have also been popular in other countries. For quite a few years, I wrote regularly for the Australian publication Guns & Game, which was owned, edited and published by my old friend Breil Jackson. An avid hunter, Breil’s primary occupation is farming. His wildcat is an improved version of the 22 Hornet case, but shortened .150 inch to make the overall cartridge length with the Hornady 40-grain V-MAX more compatible with the magazines of various rifles. His rifle has a 1:14 twist and a maximum load with 2400 powder produces a muzzle velocity of just over 2,800 fps with the Nosler bullet.

Through the years, I have accumulated rifles in 22 Hornet made by various American and foreign companies with the Winchester Model 54 and Model 70 being two of my favorites. When finding one with its chamber reamed out for the 22 Hornet Improved, I would shed a tear for future collectors while buying the rifle if the price was right.

The serial number of the Model 70 featured in this column dates to 1949 and the only clue to its chambering is “IMP” stamped to the right of the factory-applied “22 Hornet” marking on its barrel. Like all early rifles in 22 Hornet, it has a 1:16 rifling twist rate and while the groove diameter is .223 inch, it does not object to the passage of bullets measuring .224 inch. The Weaver K12 scope that came with it is early 1960s vintage and its optical quality remains good enough for bumping off varmints as far away as they should be shot with the 22 Hornet Improved.

Winchester obviously spent a lot of time and money in order to make a cartridge as tiny as the 22 Hornet feed in actions as large as the Model 54 and Model 70. In addition to drastically shortening bolt travel, a five-round, top-loaded, double-column magazine sized for the small cartridge was fabricated and then fastened to the inside of the regular internal magazine box. The machined-steel magazine follower has a wire-type spring rather than the usual flat spring.

Here is how it all works. The rim of the top 22 Hornet cartridge in the magazine does not protrude upward enough to be contacted by a bolt designed to handle much larger cartridges. The problem was solved in a very clever manner by Albert F. Laudensack, who was granted a U.S. patent for his efforts. As the bolt moves forward, a small, hinged lever at the front of the bolt drops down to contact the head of a cartridge and pushes it far enough forward for the front of the bolt to take over and chamber the round. At that point, the pusher retracts back into its slot in the bottom of the bolt where it remains until cycling is repeated. I have owned Winchester rifles in 22 Hornet for many years and functioning has been flawless for thousands of rounds.