Testing .22LR vs .22WMR

This article explores the differences in two similar, yet very different .22 caliber rimfire rounds: .22LR vs. .22WMR.

Chances are, the first shots you took were with a gun chambered in .22 Long Rifle, or .22LR as it’s known. I’m one of those people. My first shots were taken with a Marlin 60 at my uncle’s farm. I soon joined my cousins as we roamed over the prairies, looking for targets (and by that, I mean gophers). 

.22 LR ammo is inexpensive to shoot and easily controlled in all but the smallest of guns. Yet it is still powerful enough to make a tin can bounce around or drop a squirrel where it stands. While you may be familiar with .22LR, you may not know that it has a bigger brother: the .22 Winchester Magnum Rimfire, also called .22WMR or 22 Magnum. Both rounds are both rimfire cartridges, making them very different from centerfire cartridges like 9mm or .223. 

What is a rimfire cartridge? 

First, a quick review of the components that make up a round of ammo. A round of ammunition consists of four parts: the bullet, which flies downrange; the powder, which makes it go; the case, which holds the other three parts; and the primer, which is where the ignition process begins. 

The location of the primer is what separates a rimfire cartridge from a centerfire cartridge. A centerfire cartridge holds the primer in a cup in the center of the cartridge. In a rimfire cartridge, the rim of the cartridge holds the primer. 

Even though .22LR and .22WMR are both rimfire cartridges, they are not compatible with each other. With a few exceptions, guns that are chambered in .22LR will not shoot .22WMR, and vice versa. Let’s take a look at what makes each cartridge unique. 

A Brief History of .22 Long Rifle

The .22LR traces its roots back to the oldest metallic pistol cartridge in existence: the .22 Short cartridge, first introduced in 1857. The power of .22 Short came up a bit… short. So, the cartridge was lengthened to create .22 Long ammunition. In the late 1880’s, the Union Metallic Cartridge Company topped off .22 Long with larger 40 grain bullets, creating an even longer round. .22 Long Rifle was born. 

Since then, .22LR has become one of America’s most popular ammunition types, and with good reason. It is accurate enough for serious competitions, and it’s also inexpensive enough to train with on a daily basis. It’s also a decent defensive round. .22LR may not have the punch of a 9mm pistol round or the stopping power of a larger rifle round. However, the medulla oblongata and the left ventricle don’t really care if they’re hit with a 40 grain .22 bullet or a 230 grain .45 round. They’re going to stop working either way.  In fact, .22LR is the closest thing to a “do it all” cartridge. So why choose .22WMR? 

What is .22 WMR / .22 Magnum?

.22 Winchester Magnum Rimfire was created in the 1950s to address some of the issues with .22LR. It’s even longer than .22LR, and it packs more punch. .22WMR was first created by (you guessed it) the Winchester ammunition company to increase the speed of the .22 rimfire cartridge and allow for more advanced, aerodynamically efficient bullet shapes. 

While .22LR inherited it’s legacy from a pistol cartridge, .22WMR was first designed to be used in a rifle and was then adapted in the early 1960s to be used in handguns. There are several revolvers chambered in .22WMR (more on those in a bit) as well as the semi-automatic Kel-Tec PMR-30 pistol. 

What Makes Them Different? 

.22LR and .22WMR ammunition are both rimfire cartridges that shoot bullets that weigh around 40 grains. That’s where the similarities end. As was said before, most guns chambered in one caliber will not work in the other. However, Ruger makes a single-action rimfire revolver, the Convertible Single Six, that has interchangeable cylinders, one in .22LR and the other in .22WMR. 

You might be tempted to shoot .22LR in a gun that’s chambered in .22WMR. After all, the shorter length and lighter power of .22LR vs .22WMR means that, technically, it will fit into a .22WMR gun. Resist that temptation. It’s true that a round of .22LR will fit inside the chamber of a gun that shoots .22WMR. However, the .22LR fits loosely in the chamber. The .22LR cartridge case is narrower than that of .22WMR. This means it will fit in the chamber, but if you try to fire a .22LR round out of a gun that uses .22WMR, the case will expand inside the chamber when fired, to the point where it may become dangerous. 

Years ago, I had something similar happen near me at a training class. The student on my left picked up a piece of loose ammunition off the ground and slid it into his 1911. Unfortunately, the round he picked up was .40 S&W and his gun was chambered (past tense) in .45ACP. When he pulled the trigger, there was a weird noise, and I was showered with bits and pieces of broken brass as the cartridge blew apart inside the chamber and then flew out the ejection port as the gun tried to cycle. The .40 S&W round he had chambered into his .45 ACP 1911 ruined his gun. The bottom line is this: .22LR is not the same as .22WMR. Let’s go into those differences in more detail. 

Testing .22LR vs .22 WMR

We conducted two tests in order to show the differences in .22LR vs .22WMR.

For the first test, we chronographed the speed of two different rounds of both .22LR and .22WMR to compare their muzzle energies. In the second, we shot five rounds of hollow-point ammunition from both calibers into ballistics gel to test their effects on tissue. We used a Kel-Tec PMR-30 with a 4.3 inch barrel to test the .22 WMR ammunition. We used a Smith & Wesson Victory with a 5.5 inch barrel to test the .22LR ammo.

Chronograph Test

To test the speed of each round, we set up a Shooting Chrony Pro ten feet away from the muzzle and measured each of our test rounds.

CCI Max Mag 40 grain .22WMR TMJ
Maximum Velocity: 1302
Minimum Velocity: 1193
Average Velocity: 1287
Average Muzzle Energy: 140 ft/lbs

Hornady V-Max 32 grain .22WMR JHP 
Maximum Velocity: 1581
Minimum Velocity:1516
Average Velocity: 1540
Average Muzzle Energy: 168 ft/lbs

Federal 40 grain .22LR Automatch FMJ
Maximum Velocity: 1031
Minimum Velocity: 978
Average Velocity: 1010
Average Muzzle Energy: 91 ft/lbs

CCI 32 grain .22LR JSP
Maximum Velocity: 1064 fps
Minimum Velocity: 1100 fps
Average Velocity: 1081 fps
Average Muzzle Energy: 83 ft/lbs

Ballistic Gel Penetration Test

To test the penetration of .22LR vs .22WMR, we set up a block of 10% Clear Ballistics gel 10 feet away from the firing line. We placed four layers of heavy fabric in front of the gel and shot five rounds each of the following ammunition into the gel.

Hornady V-Max 32 grain .22 WMR JHP

1. Penetration Depth: 16.25 inches
2. Penetration Depth: 16.5 inches
3. Penetration Depth: 16 inches
4. Penetration Depth: 15.5 inches
5. Penetration Depth:  12.25 inches

Average Penetration: 15.3 inches

CCI 32 Grain .22LR JSP

1. Penetration Depth: 7.375 inches
2. Penetration Depth: 7.25 inches
3. Penetration Depth: 6.5 inches
4. Penetration Depth: 6.25 inches
5. Penetration Depth: 5.5

Average Penetration: 5.575 inches

The .22WMR rounds penetrated significantly more than the .22LR. The polymer tip on the hollow point V-Max bullet did not cause the rounds to expand in any measurable way. The hollow point .22LR rounds, however, all expanded and broke apart inside the gel. 

Conclusion

.22WMR is a much more powerful round than .22LR. It has almost twice as much muzzle energy as .22LR in some rounds, which gives it more punch when it hits the target. When a round of .22WMR hits the target, it can penetrate almost three times as far as .22LR. 

.22LR is a great round that is still going strong today, over 125 years since it first came out. It’s inexpensive and easy to shoot, making it a popular cartridge for plinking, target practice, and varmint hunting. It will continue to be popular for decades to come. 

.22WMR, on the other hand, costs more per round than .22LR, but it delivers more punch. The higher velocity and deeper penetration of the .22WMR place it on the edge of being a viable self-defense round. The choices for guns that shoot .22WMR, though, are much more limited than the choices of guns that shoot .22LR. This combination of higher shooting costs and fewer choices in firearms makes .22WMR a niche cartridge, but that niche is growing every day as people see the advantages of a low-recoil, easy to shoot defensive cartridge like .22WMR.