22 Magnum vs 5.7x28

So, you want the FN 5.7x28mm NATO, but just can’t decide if there’s enough difference over the 22 magnum? While these cartridges may be similar on paper, they provide many differences that make for a difficult decision. In this article, we will be going over some of these similarities and differences to help make your decision a little easier.

Physical Attributes

Other than firing 22-caliber projectiles, the 22 magnum and the 5.7x28 could not be farther apart in terms of physical attributes. In fact, they do not even share the same priming mechanism, as the 22 WMR (Winchester Magnum Rimfire) is a rimfire cartridge, whereas the 5.7x28 is a centerfire cartridge.

Unlike the 5.7x28, which uses a replaceable primer found in the center of the base of the case, the 22 magnum utilizes primer compound throughout its rim. If the primer compound is absent from a portion of the rim, a misfire could occur if the firing pin were to hit this dead area. Although rimfire technology has come a long way, misfires are still much more common than they are with centerfire cartridges.

Because of this, centerfire cartridges are considered ideal for self-defense scenarios, where ensured reliability is critical. That is not to say that centerfire cartridges will never fail. However, they have proven to be more reliable than rimfires.

Not only are centerfire cartridges more reliable than rimfire cartridges, but they also provide the added benefit of being reloadable (in many cases). This reloadability comes from the primer being an easily replaced part, unlike the captured primer compound found in rimfires.

Moving away from the priming mechanism, we see a distinct difference in height. With a maximum overall length of 1.594 inches, the 5.7x28 stands nearly a quarter inch taller than the 22 magnum’s maximum overall length of 1.350 inches. Much of this height, however, can be attributed to the style of bullet loaded in each, as the difference in case length is only 0.083 inches between these cartridges.

Perhaps the most noticeable difference between these cartridges, however, is their shape. While the 5.7x28 case may be slightly longer than the 22 magnum, its bottleneck design makes for a much wider case overall. This additional width greatly increases the powder capacity of the 5.7x28 when compared to the straight-walled design of the 22 magnum.

It should also be noted that the 5.7x28 features a rimless case design, whereas the 22 magnum features a rimmed design. While ideal in lever actions and revolvers, a rimmed design can lead to reliability issues in semi-automatic weapons. This is primarily due to its geometry, which can lead to issues if magazines are not properly designed or loaded.

Power

Being that the 22 magnum and the 5.7x28 use a similar weight range of 22 caliber projectiles, it would be easy to think that they provide similar performance. This, however, is not the case, as the 5.7x28 produces just over twice the pressure of the 22 magnum. This increased pressure, paired with its larger powder charge, leads to a distinct difference in power between these cartridges when fired from similar setups.

When looking at Federal’s 40-grain FMJ load in 22 WMR, we see that it produces 314 ft/lbs. at a muzzle velocity of 1,880 feet per second. If we look at Federal’s 40-grain FMJ load in 5.7x28 (very different bullet shape), we see that it produces 243 ft/lbs. at a muzzle velocity of 1,655 feet per second.

But how could the 22 magnum possibly produce 29.2 percent more muzzle energy than the 5.7 when it’s only producing half the pressure? The answer comes down to barrel length. Because most 5.7x28 chamberings are pistols, Federal’s velocity rating is from a 4.8-inch barrel.

Although the 22 WMR is commonly chambered in pistols, it is much more common in rifles, which explains this higher velocity rating. If the same 22 magnum load were fired from a PMR-30 (5-inch threaded barrel), the muzzle velocity drops from 1,880 feet per second to approximately 1,450 feet per second.

This equates to a muzzle energy of 187 ft/lbs., which is just over 40 percent less than the listed figures and about 23 percent less than the muzzle energy of the 5.7x28. So, although the velocities listed on the boxes may trick you into thinking otherwise, the 22 magnum and the 5.7x28 offer very different muzzle energy figures out of similar setups.

Cost

With its higher muzzle energy figures and centerfire design, the 5.7x28 makes for a better choice in carry guns. But let’s say that rather than using this firearm as a carry gun, you will almost exclusively be using it at the range. In that case, power probably doesn’t matter to you as much as price, as both cartridges are capable of punching 22-caliber holes on paper. 

Regardless of the offering, you will notice a large difference in price between the 5.7x28 and the 22 magnum. Although the 5.7x28 is not expensive compared to many rifle cartridges, current prices rival those of the 5.56 NATO, which is a superior (at least ballistically) cartridge.

This pricing places the 5.7x28 at nearly 3 times the cost of most 22 magnum loads, meaning that you could fire the 22 magnum three times for every shot of 5.7x28 (in many cases). While the 5.7x28 does offer more power, it’s easy to see that range days would be much shorter when compared to the 22 magnum, unless you have an unlimited budget.

It should be noted, however, that although current 5.7x28 prices may be high, many manufacturers are starting to produce load offerings for the cartridge. These new load offerings not only give additional choices, but they could also help to lower prices in the future.

For now, however, there is no comparison between the cost of 22 magnum and 5.7x28 ammunition.

Which One

While the 22 magnum and the 5.7x28 may be similar on paper, they are very different cartridges with different capabilities. So, the question is, which one should you go with?

If you’re primarily looking for a self-defense cartridge, the 5.7x28 wins the argument specifically based on its centerfire design. Its higher muzzle energy figures also lead to arguably better performance than the 22 magnum when fired out of similar setups. One thing you must remember, however, is that you will be paying for this increased performance.

Although the 22 magnum may be a capable cartridge for self-defense, its rimfire design is not well-suited for the task. The 22 magnum does, however, offer a lot of performance for its much lower price, especially if you’ll only be using it at the range, where reliability is not life or death.

Regardless of which cartridge you choose, hopefully, this article helps make your decision a little easier.

--Banana Ballistics