The .223 WSSM
By Chuck Hawks
The .223 WSSM factory load that Olin/Winchester recommends for hunting antelope, deer, and black bear drives a 64 grain Power Point bullet (SD .182) at an advertised muzzle velocity (MV) of 3600 fps and muzzle energy (ME) of 1841 ft. lbs. Clearly the primary limiting factors of this load as a deer cartridge are neither its energy nor its trajectory but rather its frontal area, weight, and sectional density.
The Winchester Super-X .223 WSSM factory load with the 64 grain Power Point bullet is simply inadequate for shooting North American deer and antelope, regardless of the velocity at which it can be driven by any .22 caliber cartridge ever produced. It is even more inadequate for black bear, not to mention illegal in some jurisdictions.
Now let's take a look at the Winchester figures for the .223 WSSM's varmint loads. There are two, a 55 grain Supreme Ballistic Tip bullet and a 55 grain Super-X Pointed Soft Point (PSP) bullet. Both are recommended for use on prairie dogs, woodchucks, and coyotes. These are sound recommendations; they are exactly the same animals that are humanely are taken with a 55 grain bullet from a .22-250 or a .220 Swift.
The WSSM calibers are factory loaded close to the allowable maximum average pressure, which means that reloaders are unlikely to be able to safely better published velocities. However, it is possible to approximately equal the published velocities with carefully assembled maximum reloads using 55 grain bullets fired from rifles with 24" barrels. And, of course, reloaders can play around with bullets from 40 to 70 grains in weight, although the 55 grain spitzer bullet will probably prove to be the most useful, just as it has in the other big capacity .22's.
The sixth edition of the Hornady Handbook relates that "this cartridge is hard on barrels," with significant throat erosion visible after only 350 rounds had been fired. VARGET proved to be an excellent powder for bullets ranging from 40-60 grains, and IMR 4350 gave the best results with heavier bullets. Note that the best accuracy from the .223 WSSM has been reported using loads slightly below maximum.
The Hornady 50 grain bullets achieved a MV of 3700 fps in front of 38.0 grains of VARGET powder, and a MV of 3900 fps with 40.4 grains of VARGET.
Using Hornady 55 grain bullets, 35.5 grains of VARGET gave a MV of 3500 fps, and 39.6 grains gave a MV of 3800 fps.
The Hornady 68 grain BTHP bullet was driven to a MV of 3200 fps by 38.4 grains of IMR 4350 powder, and to a MV of 3600 fps by 34.7 grains of IMR 4350.
The Hornady technicians used Winchester WLR primers and their custom Browning test rifle had a 26" barrel.
Note: A more extensive article about the .223 WSSM can be found on the Rifle Cartridge Page.
Copyright 2004, 2012 by Chuck Hawks. All rights reserved.