Compared: The .223 WSSM and .220 Swift

By Chuck Hawks

The WSSM cartridges received plenty of press at their introduction, and the claims made for the .223 WSSM practically begged that the cartridge be compared to the established .220 Swift in articles such as this one. The .220 Swift is the reigning king of .22 caliber varmint cartridges. Winchester, of course, prefers to compare the .223 WSSM to the .223 Remington and .22-250 Remington, cartridges with less powder capacity than the .223 WSSM. These unfair comparisons insure that the .223 WSSM "wins" in terms of maximum performance.

The .223 WSSM and .220 Swift are maximum performance, long range varmint cartridges. And that is how they will be evaluated in this article.

The .220 Swift became the performance leader in the varmint cartridge sweepstakes when Winchester introduced in 1935 and it retains that title today. It is based on the semi-rimmed 6mm Lee Navy case necked down to accept .224" bullets. This case is 2.205" long and has a 21-degree shoulder angle. It will work through all short (.308 Winchester length) rifle actions.

The .220's claim to fame and the reason for its handle "Swift" is its original factory muzzle velocity (MV) of 4110 fps and muzzle energy (ME) of 1800 ft. lbs. with a 48 grain bullet. The 48 grain bullet has been discontinued, but 40-50 grain bullets at MV's from 4019 fps to 4200 fps are still offered. The .220 also quickly gained a reputation for pinpoint accuracy, which it retains to this day.

Ultra high velocity means ultra-fast barrel wear, as early Swift experimenters quickly discovered and .223 WSSM experimenters are rediscovering. (Browning has been forced to delay the intorduction of their WSSM rifles while they try to solve this problem.) Reloaders soon found that somewhat reduced loads using heavier bullets gave much better barrel life and were more practical in every way for serious long range varminting. These are now available as factory loads from a number of manufacturers. Federal's version drives a 55 grain bullet at a MV of 3700 fps.

Ultra-high velocity also led some hunters to try their Swift rifles on deer and antelope, with mixed results. Sometimes, when the bullet met little resistance on its way to a vital spot, an almost instant kill was the result. And sometimes the bullet blew up before reaching the vitals and animals ran off with terrible surface wounds, never to be seen again. Eventually the hunting of deer and antelope (or any big game animal) with .22 caliber varmint cartridges became illegal in most states. But these failures to anchor big game needlessly tarnished the .220's reputation.

Although the problems of short barrel life were ameliorated by tougher steel and reduced velocity loads, and the .220 was eventually outlawed for use on big game, the cartridge had gained a somewhat checkered reputation. In 1964 Winchester decided to replace the Swift in their Model 70 bolt action rifle line with the new .225 Winchester cartridge, a move that served only to move the .22-250 Remington to the fore in sales. Within a few years Winchester recognized their mistake and the .225 was gone from the Model 70 line. The .220 has never caught up with the .22-250 in sales, but it has made a solid comeback and is now chambered in several rifle models. In North America .220 Swift factory ammunition is available from Federal, Hornady, Norma, PMC, Remington, and Winchester.

The .223 WSSM (for "Winchester Super Short Magnum") was announced in 2002. It is based on a shortened .300 WSM case only 1.7" long, designed for a new action size about 1/2" shorter than a normal (.308 Win. length) short action. A shorter action produces a shorter and somewhat lighter rifle, something of a moot point when the natural home of the cartridge is a varmint rifle with a long, heavy barrel, and where weight is considered an asset rather than a liability. Like the .220 Swift, the .223 WSSM uses standard .224" diameter bullets.

Winchester offers two factory loads for the .223 WSSM that are intended for varmint shooting, a 55 grain Combined Technologies (i.e. Nosler) Ballistic Silvertip bullet and a 55 grain soft point bullet. The former has a pointed plastic tip and a boat-tail; the latter is a standard spitzer bullet with a flat base. The third Winchester offering in .223 WSSM is a 64 grain Power Point (soft point) flat base spitzer bullet intended for use on deer and antelope--I kid you not! This is not a frangible bullet and should not be used for varmint shooting. For more on this subject, see my article "First Look: The .223 WSSM" on the Rifle Cartridge Page.

Unlike the svelte Swift, the .223 WSSM is a very fat, very stubby, rebated rim design with a sharp shoulder. It is a case shape optimized for accuracy, as per popular bench rest cartridges such as the .22 PPC.

That this is a difficult shape to feed from the box magazine of a typical push feed bolt action rifle should be clear to any experienced observer, although you would not believe the flack I have caught in some quarters for pointing this out. Winchester (Olin) and their partner Browning discovered this to their embarrassment at the press introduction of the new WSSM cartridges and rifles, where the sample super-short action Browning A-Bolt II WSSM rifles repeatedly jammed. (The A-Bolt II uses a push feed action.) Browning has been forced to delay the release of their WSSM rifles while they work on this and the problem of excessive barrel erosion. The bulk of the gun press--ever compliant to the wishes of advertisers--failed to report this, although they lavishly, even unrealistically, praised the performance of the new cartridges.

Winchester (U.S. Repeating Arms) has tried to circumvent the feeding problem by the introduction of a hybrid "controlled push feed" action designed specifically for the WSSM cartridges. Winchester has also introduced a super short action version of their "Classic" controlled feed Model 70 Featherweight. Evidently Winchester feels that they have the feeding problem licked--and they are not offering WSSM cartridges in their push feed rifles.

Like its running mate the .243 WSSM (which is the ballistic twin of the standard 6mm Remington), the .223 WSSM offers nothing in terms of its ballistics that cannot be accomplished by existing non-magnum cartridges. However, any cartridge that can essentially duplicate the ballistic performance of the Swift deserves to get a close look in an article such as this.

Let's start with factory loads, and then move on to reloads. Selected factory loads for the .220 Swift are listed below, along with the Winchester loads introduced for the .223 WSSM. (Caliber, bullet weight mfg. type - MV, ME.)

  • .223 WSSM, 55 grain Win. BSt - MV 3850 fps, ME 1810 ft. lbs.
  • .223 WSSM, 55 grain Win. PSP - MV 3850 fps, ME 1810 ft. lbs.
  • .223 WSSM, 64 grain Win. PP - MV 3600 fps, ME 1841 ft. lbs.
  • .220 Swift, 40 grain Hor. V-Max - MV 4200 fps, ME 1566 ft. lbs.
  • .220 Swift, 50 grain Nor. SP - MV 4019 fps, ME 1794 ft. lbs.
  • .220 Swift, 55 grain Fed. SPBT - MV 3800 fps, ME 1765 ft. lbs.
  • .220 Swift, 60 grain Hor. HP - MV 3600 fps, ME 1727 ft. lbs.

It is worth noting that most .220 Swift rifles come with 24" or 26" barrels and deliver close to the muzzle velocity specified from factory loads. Most .223 WSSM rifles come with 21" and 22" barrels and actually deliver anywhere from about 130 to 230 fps less MV than claimed.

The .223 WSSM is factory loaded very close to its maximum allowable SAAMI pressure, which I understand is 52,000 cup. This means that reloaders will be hard pressed to equal the claimed velocity of the factory loads, which should be taken as maximum. The .220 Swift is also loaded pretty "hot," but usually not quite to its SAAMI maximum average pressure limit of 54,000 cup. Here are a couple of maximum .220 Swift reloads from the fifth edition of the Nosler Reloading Guide to compare to a preliminary maximum .223 WSSM reload. These loads were chronographed in actual hunting rifles (not SAAMI test barrels), and the lower velocity of the .223 WSSM is almost certainly due to the shorter barrel of its rifle.

  • .223 WSSM, 55 grain Nosler BSt - MV 3710 fps
  • .220 Swift, 55 grain Nosler BSt - MV 3852 fps
  • .220 Swift, 60 grain Nosler Par. - MV 3715 fps

Hmm . . . not much difference in either factory loads or reloads is there? I think it would be fair to conclude that what one cartridge can do, the other can also do equally well.

Just for the record, the trajectory of both calibers is identical since both can drive the same bullets to the same muzzle velocity. According to the "Rifle Trajectory Table" the maximum point blank range (MPBR) of either caliber, calculated for a maximum deviation of 1.5" above or below the sight line of scoped rifle, using a 55 grain Hornady Spire Point bullet at a MV of 3800 fps, is 264 yards.

Back the muzzle velocity off to 3600 fps (about like that of a .22-250) and the MPBR drops to 254 yards, a reasonable trade-off for longer barrel life and perhaps better accuracy. Most varmint hunters are unlikely to miss the 10 lost yards.

Increase the allowable deviation from the line of sight to +/- 2" and the MPBR increases to 300 yards with maximum loads. This is about as good as it gets for .22 caliber varmint rifles!

Both the Swift and the .223 WSSM have the inherent accuracy (in a good rifle) to make use of such flat trajectories. Long before the .223 WSSM was invented, Jack O'Connor wrote this about the .220 Swift in his Gun Book: "The varmint shooter with a Swift in his dukes is fresh out of alibis. If he doesn't make a hit on a still day it's because he didn't hold right or because he yanked the trigger." And he added, "A Swift is wasted on a poor rifleman."

Since the .223 WSSM and .220 Swift can use the exact same bullets, there is no difference between the two cartridges in sectional density, ballistic coefficient, bullet frontal area, or bullet terminal performance. Because they can achieve the same velocity with the same bullets, there is no difference in energy. Thus the killing power of the two cartridges is identical.

Killing power is not much of an issue with .22 centerfire rifle calibers in any case. All have sufficient killing power for varmints well beyond their MPBR, and none are sufficient for even the smaller species of North American deer or pronghorn antelope.

The .220 Swift is inherently a more suitable design than the .223 WSSM from the standpoint of feed reliability, but that is not a big issue for a varmint rifle. A fast repeat shot is seldom required. In fact, many of the best varmint rifles are single shot models. This is true of bolt action as well as falling block varmint rifles.

The .223 WSSM is potentially a slightly more accurate cartridge design than the Swift, but there are many more important factors influencing the actual accuracy of any rifle/cartridge/load combination than the shape of the cartridge case. The Swift has proven more than sufficiently accurate for all varminting purposes within its effective range. As a point in fact, typical 5-shot groups from a 100 yard bench rest with Browning and Winchester .223 WSSM rifles run from about .75" to 1.25", which is excellent practical accuracy, but no better than typical groups from .220 Swift rifles. So accuracy is also not an issue when comparing these two varmint cartridges.

The .223 WSSM and .220 Swift are ballistically equal and both possess more than adequate accuracy to take full advantage of their maximum point blank range. Thus any decision between the two will depend on other factors, such as the availability of factory loaded ammunition, the availability of rifles on the new and used markets, or simple personal preference.

In terms of the availability of ammunition, the Swift has the advantage. As of this writing .223 WSSM factory loaded ammo is available only from Winchester, while many companies load .220 ammunition.

The choice of new rifles is somewhat limited for both calibers, and neither enjoys a clear advantage. Since the Swift has been around since 1935, there are used .220 rifles available, while I have yet to see a used .223 WSSM. The Swift clearly has the advantage in terms of used rifles.

As to personal preference, as far as the cartridges themselves are concerned, the shooter who must have the latest fad will likely choose the .223 WSSM simply because it is new. The more conservative shooter will likely choose the established .220 Swift, with its proven track record.

A more important consideration is what rifle best fits the prospective owner, both physically and subjectively. Browning, for example, offers A-bolt II rifles in .223 WSSM but not in .220 Swift. Ruger, on the other hand, offers their fine No. 1 single shot in .220 Swift but not in .223 WSSM. The shooter whose ultimate varmint rifle is an A-Bolt is going to have to buy it in the WSSM caliber, while the person who finds the No. 1 to be their perfect varmint rifle is going to have to go with the Swift. In either case, success in the field will be a function of the shooter's skill with the rifle, not the cartridge selected.

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Copyright 2003, 2012 by Chuck Hawks. All rights reserved.