.22 Caliber "Big Game" Rifle Cartridges
By Chuck Hawks
The use of .22 centerfire rifles on the smaller species of big game has a long but checkered history, dating back at least to the 1912 commercial introduction of the .22 Savage High-Power. This obsolete rimmed cartridge, designed by Charles Newton, was based on the .25-35 case necked down to accept a 70-71 grain .228 inch diameter bullet. Europeans adopted the .22 Savage High-Power for use in drillings and double rifles; there it is known as the 5.6x52R, and Norma of Sweden still offers 5.6x52R factory loads. In North America the .22 High-Power proved better for varmints and small game than deer, and significantly inferior to its parent the .25-35 for deer and antelope. (This would become a familiar refrain about .22 big game cartridges, as we shall see).
The great majority of subsequent centerfire .22's were designed or adapted for use as varmint and small game cartridges. This includes all of the commonly available North American .22's, including the .22 Hornet, .221 Fireball, .218 Bee, .222 Remington, .223 Remington, .22-250 Remington, .224 Weatherby, and .220 Swift.
Modern .22 centerfire cartridges, regardless of nomenclature, use standard .224 inch diameter bullets. The exception is old .22 Hornet rifles, which use .223 inch diameter bullets. Modern Hornet rifles use .224 inch bullets.
Rifles for the .22 centerfire calibers generally have barrels with twist of 1 turn in 14 inches. The exceptions are the .22 Hornet, whose light bullets only require 1 in 16 twist, and the .223 Remington, which was developed for military use in the M-16 infantry rifle and usually has a 1 in 12 twist as a civilian varmint rifle. These twist rates are intended to stabilize spitzer bullets weighing up to about 55 grains over hunting ranges in the small to medium size cases, and up to about 64 grains in the .223 and the three larger capacity cases. Twist rates of 1 in 10 or faster can cause lightly constructed .22 caliber varmint bullets to distort or come apart in flight at high velocity, and are not normally used for centerfire .22 rifles.
When Remington introduced the .223, which one month later was adopted by the U.S. military as the 5.56mm NATO cartridge, they intended it for use on varmints and loaded bullets specifically intended for that purpose. But many inexperienced hunters falsely assumed that if the .223 were good enough for the Armed Forces to use on enemy soldiers, it must be powerful enough for deer hunting.
Nothing could be farther from the truth, as the requirements for a modern military cartridge are quite different from those of a modern medium game cartridge. Hunters do not use fully automatic weapons, or lay down fire-suppressing barrages, or have ammunition air lifted to them by helicopter. Hunters are not interested in causing "casualties," they need one shot kills.
Use my "Optimal Ranges for Big Game" chart to compare the killing power of the .223 Remington with a 60 grain Nosler Partition bullet (probably the deadliest bullet suitable for the caliber) to cartridges like the .243 Winchester, 6mm Remington, .250 Savage, .257 Roberts, or even the old .25-35. You will find that the numbers are not encouraging.
.22 caliber bullets have some serious drawbacks for use on medium game such as deer, antelope, sheep, and goats. Most obvious is their very small cross sectional area.
Cross sectional area is an important factor in killing power. The bigger the wound channel made by a bullet, the more tissue is destroyed or damaged, and the quicker the animal succumbs to the wound. That is why all bullets used for hunting medium game must be of the expanding type; expansion increases cross sectional area. But it requires time and distance after impact for bullet expansion to take place. And, other things being equal, a larger diameter bullet makes a larger diameter mushroom after expansion has taken place. Perhaps you remember from high school math that a small increase in the diameter of a circle (a bullet in cross section is a circle) causes a much greater increase in the area of that circle. So it is that the relatively small increase in bullet diameter from .224 inch to, say, .243 inch or .257 inch actually results in a bullet with a significantly greater cross sectional area, and consequently a larger wound channel.
The other glaring weaknesses of .22 bullets are their relatively poor ballistic coefficient (BC) and sectional density (SD). Remember, BC indicates how efficiently a bullet penetrates the air, which affects bullet trajectory and wind drift. SD is a function of a bullet's weight compared to its diameter, and has a major affect on penetration.
A relatively heavy .224 inch bullet, in this case the Nosler 60 grain Partition spitzer, has a BC of .228 and a SD of .171. These are not impressive numbers and reveal the limitations of the centerfire.22's for use on medium size big game. (For comparison, a 90 grain Nosler Ballistic Tip .243 bullet has a BC of .365 and a SD of .218.)
When the prey weighs 5 to 15 pounds penetration is not much of an issue, and the very high velocities that can be obtained with light 45-55 grain bullets allow a flat trajectory over typical varmint shooting ranges (which seldom extend past 250 yards). A high velocity bullet that hits anywhere in the torso of a small animal is very likely to be fatal. If the wind blows the bullet clear off the target it makes little difference: there are more woodchucks or prairie dogs at which to shoot.
But, of course, things are different when big game hunting. The average deer hunter will be lucky to get one shot in an entire year and he needs a bullet with sufficient sectional density to penetrate deep into the animal's vitals, and sufficient expanded cross sectional area to create a wound that kills quickly. A miscue caused by wind drift may mean a gut shot animal and a long and frustrating chase. A 100-200 pound animal is a very different proposition from a 5-15 pound animal!
In Europe the situation is somewhat different. The modern 5.6x50 Magnum, 5.6x50R, and 5.6x57 RWS, as well as the obsolete 5.6x61 and 5.6x61R Vom Hofe cartridges, were all developed for use on small deer and goats.
The European deer in question are Roe buck and the goats are chamois. These diminutive creatures average about 50 pounds on the hoof and are fair game for the European .22 centerfire cartridges that have been developed for hunting them. The new .223 WSSM and older .220 Swift, with similar ballistic capability, would also serve for this kind of hunting if they were used with the Winchester 64 grain Power-Point or Nosler 60 grain Partition bullets.
But the .220 Swift has a 70 year long track record of failures on the much larger North American deer and pronghorn antelope. The .220 Swift is a varmint cartridge based on the old 6mm Lee Navy case. It was introduced by Winchester in 1935. The original factory load featured a 48 grain bullet at a muzzle velocity in excess of 4100 fps. It wasn't long before intrepid hunters tried the .220 on deer and antelope, but the results were mixed. Sometimes spectacular quick kills were the result, but sometimes the .220 bullets failed to penetrate or failed to create an adequate wound channel and a wounded animal escaped to die a long and painful death. Ultimately, the .220 Swift proved a less reliable deer caliber than the 6mm Lee cartridge from which it was derived, and use of the Swift on medium game faded away.
A correspondent sent me an article called "The .224 Texas Trophy Hunter (TTH)" by Horace Gore with Ralph Lermayer for my perusal. This article describes a new American .22 wildcat intended for deer and antelope hunting. This cartridge was developed in Texas, as you might guess from the name. It is based on the 6mm Remington case necked down to accept .224 inch bullets. The rifling twist is a very fast 1 turn in 8 inches to allow for the stabilization of bullets weighing up to 85 grains. The .224 TTH is an attempt at an ultimate .22 caliber big game cartridge. The .223 WSSM, introduced by Winchester as a commercial cartridge a year or so later, is the ballistic twin of the .224 TTH.
The previously mentioned 5.6x57 RWS cartridge, introduced in 1964, is a similar attempt. It is factory loaded in Germany and is moderately popular in parts of Europe. The 5.6x57 and .224 TTH have similar capacity cases and similar ballistics. The .224 TTH is conceptually an American version of the 5.6x57 RWS, although its designers may have been unaware of the older, established German cartridge. Winchester designers were probably aware of both, and this likely helped spur the introduction of the .223 WSSM.
The .224 TTH cartridge was allegedly developed because Texas big game guides found that many of their sports were unable to shoot their powerful magnum rifles accurately. (A common complaint among professional guides everywhere.) These guides began carrying .223 and .220 rifles in their vehicles to loan to customers hunting the relatively small Texas whitetail deer. Eventually the idea of a larger capacity .22 centerfire cartridge, designed from the outset for Texas whitetail deer and pronghorn antelope hunting, took hold in certain quarters (particularly the Texas Trophy Hunters organization) and the result is the .224 TTH.
After reading Mr. Gore's article, I added the .224 TTH to the expanded versions of the "Rifle Recoil," "Rifle Trajectory," and "Optimum Game Weight" tables so that it could be compared to other cartridges. I used the figures quoted in the .224 TTH article, an 80 grain spitzer bullet (SD .228) at a MV of 3650 fps from a 26 inch rifle barrel. Unfortunately, this load cannot be easily duplicated as the 80 grain bullet described in the article was custom made for testing the .224 TTH and is not commercially available. Winchester factory loads, including the 64 grain Power-Point bullet, for the .223 WSSM are also included in those tables.
You can view these tables on the "Tables, Charts and Lists Page" of Guns and Shooting Online. There you can compare the killing power, recoil, and trajectory of the high velocity .224 TTH handload using the custom made 80 grain bullet to the parent 6mm Remington cartridge. The 6mm Remington load I chose for comparison uses an ordinary 95 grain Nosler Ballistic Tip bullet (SD .230) in front of a maximum load of RL22 powder and was taken from the Nosler Reloading Guide. This load was chronographed at a MV of 3260 fps in a rifle with a standard 24" barrel, not the longer 26" tube used by the .224 TTH test rifle.
After making that comparison it became obvious that necking the 6mm Rem. case down to .224 and using a custom made 80 grain bullet gained practically nothing compared to the original 6mm Remington cartridge. As might be expected, killing power was somewhat less, recoil was reduced by only 0.4 ft. lb., and the maximum point blank range was increased from 313 yards to 338 yards. The biggest difference, of course, is that factory loaded ammunition and factory made rifles are not available for the .224 TTH cartridge.
Using commercially available 60 grain bullets the .224 TTH is very inferior in killing power to all modern .24 and .25 caliber combination varmint and deer cartridges. The mild .250 Savage has an 85 yard advantage in optimum killing range on 200 pound animals, and an even greater advantage on 100 pound game. Much the same conclusion will be reached if the .223 WSSM is compared to the similar (except for caliber) .243 WSSM.
As much as I favor low recoil cartridges, I find it hard to believe that the recoil of a 7.5 pound 6mm Rem. rifle (10.6 ft. lbs.) is beyond the ability of Texas deer hunters to control, while the recoil of a 7.5 pound .224 TTH rifle (10.2 ft. lbs.) is easily handled by the same guys. 0.4 ft. lb. of recoil energy must be more significant to Texas trophy hunters than it is those hunting in other parts of the country.
I will grant that the .224 TTH and .223 WSSM will undoubtedly do for small deer and antelope under the right conditions and with careful bullet placement. However, exactly the same thing can be said for the .243 Winchester, 6mm Remington, .250 Savage, and other cartridges with modest recoil. To quote briefly from an article about the 6mm Remington written by Arthur Alphin: "Experimenting with how light a caliber can actually be effective on deer may be fun for the rifleman though I rest confident that it is decidedly less fun for the wounded deer which struggles to get away when hit with bullets of inadequate weight, inadequate cross sectional area, and inadequate energy."
My conclusion is that even if the .224 TTH were as good a deer cartridge as its parent the 6mm Remington (which is a stretch in itself), it is not worth the time and expense involved to have a custom rifle built for a wildcat cartridge designed to use obscure bullets and for which there is no factory loaded ammunition available. As to the .223 WSSM, it is very difficult to imagine why any deer hunter would choose that cartridge when the nearly identical and much more effective .243 WSSM is available in exactly the same rifles.
I have spent time discussing the .224 TTH to illustrate some of the drawbacks inherent in even the best .22 caliber big game cartridge. To make any .22 caliber rifle cartridge even marginally suitable for North American deer and antelope hunting requires sacrifices in areas such as bullet cross sectional area, sectional density, killing power, and availability of rifles, ammunition, and reloading components for precious little gain in recoil reduction.
Many experts believe that even the popular .24 caliber cartridges are inadequate for deer hunting due to insufficient bullet cross sectional area. I am not among them. I do think, however, that .243/6mm represents the minimum practical bore diameter for hunting North American deer, antelope, sheep, and goats.
Copyright 2002, 2012 by Chuck Hawks. All rights reserved.