5.7x28mm For Self Defense; Is it a glorified .22WMR?

Per popular demand on Facebook, I’m doing my own analysis of 5.7x28mm for it’s use for self-defense. Undoubtedly, the new refound interest in the caliber is due to Ruger introducing a budget friendly pistol chambered in this caliber. Right off the bat though let’s get some disclaimers out of the way.

  1. I do not own a pistol in 5.7x28mm, I think the caliber is too expensive to use as a defensive caliber due to training costs.
  2. I did not do my own ballistics tests. The information in this post is from a conglomeration of data produced by other content producers

5.7x28mm has become somewhat of a “sacred cow” to some. It’s capabilities have been over-exaggerated and the owners of guns in this caliber drool at the mouth at the very thought of body armor. Meanwhile a whole other group of individuals starts to get white stuff around their mouth because they can’t refrain from calling it a glorified .22 Magnum.

Is the hype real? Or is it a glorified .22 Magnum? Beyond handguns, does the P90 have any use as a PDW?    Well, let’s find out.


First, let’s talk about the armor penetrating capabilities. 5.7x28mm was designed to be slung out of the P90, which has a ~10″ barrel. Out of that 10″ barrel it seems that any 5.7x28mm loading will penetrate soft body armor, but that’s where the fun ends. With the current 5.7x28mm ammunition having been designed around a 10″ barrel, it isn’t going to have the same capabilities out of a 4.8″ barrel; that’s just science.

Out of a handgun, 5.7x28mm will only penetrate soft armor with specific ammunition, but with the right sectional density and velocities nearly any caliber can defeat soft body armor (if you’re an armor nerd, correct me if I’m wrong). The excitement is, is that the soft body armor killing 5.7x28mm ammunition is relatively easy to come by compared to other pistol calibers.

Side Note: If you’re looking at the P90 as a PDW due to it being able to pierce IIIA soft armor, remember. 5.56 can do the same thing, while costing considerably less per round to train with.


Image From: Dad

Speaking of the P90, how does it stack up compared to other PDWs? Well, poorly.

I know, I know. The Secret Service uses it, blah, blah blah, but I have some valid reasons here.
1. It can’t be suppressed well. At the velocities required for it to be suppressed well, the cartridge isn’t doing much more than a watered down .22 Magnum.

2. .45 ACP subguns exist and .45 ACP itself is usually subsonic even out of 10″ barrels, while costing about half of what 5.7x28mm costs (Did I mention that finding subsonic 5.7x28mm is like…impossible?).

3. 300BLK and 5.56 subsonic loads exist, both of which deliver superior ballistics to 5.7x28mm.

All around, I just don’t see the P90 as being a good option for personal defense or home defense, so let’s move on.


Is it a glorified .22 Magnum? Well, if we go based off of velocities and energy levels purely, no. To give you some context, here are some numbers:

5.7x28mm from a 10.3″ barrel- Wikipedia
SS90: 2,800 ft/s | 400 ft/lb
SS190: 2,350 ft/s | 394 ft/lb
SS195LF: 2,350 ft/s | 344 ft/lb

.22WMR (magnum) from a 24″ barrel- Wikipedia
30gr HP: 2,300 ft/s | 322 ft/lb
40gr JHP: 1,875 ft/s | 324 ft/lb
50gr JHP: 1,530 ft/s | 300 ft/lb

5.7x28mm from a 4.8″ barrel (FN Five-seveN)- Wikipedia
SS195: 2,050 ft/s | 260 ft/lb
SS190: 2,100 ft/s | 313 ft/lb

.22WMR (magnum) from a 4.6″ barrel (Heritage Rough Ryder)-Ballistics By The Inch
Hornady 30gr V-Max: 1,144 ft/s | N/A
CCI Maxi-Mag 40gr JHP: 1,049 ft/s | N/A

As you can see, out of a 24″ barrel .22 Magnum struggles to keep up with 5.7x28mm out of a 10.3″ barrel. Out of handgun sized barrels (4.6″ and 4.8″) it doesn’t even hold a flame to what is Speedy Gonzalez. Now, you could say that the .22WMR had an unfair disadvantage in the bottom half. It had 0.2″ less barrel and cylinder gap to contend with…but no one is going to say that accounts for being 1,000 ft/s slower than 5.7x28mm.

Normally this is where this subject dies, the numbers prevail, and both parties go to their respective corners, but not today! Today, we’re digging deeper and looking at the gelatin tests I can track down.


Needless to say, good ballistic tests of 5.7x28mm are few and far between. There’s very few where it isn’t being tested against barriers and even fewer that actually test for consistency. Never fear though, I love drawing conclusions from incomplete data sets!

Image from MrGunsNGear

One of the better tests I saw was from Shooting The Bull (video here) where the 5.7x28mm didn’t exactly produce what I would call “consistent results”. In his testing the SS197 “Sporting Round” for the 5.7x28mm reached penetration depths of 12″ up to 15.75″ in a 5 shot group. In MrGunsNGear’s SS195 video, the cartridge failed to even reach the 12″ minimum set by the FBI’s protocols.

Will 5.7x28mm meet the minimum requirements set forth by the FBI’s protocols for testing ammunition? I would say 100% out of FN’s P90, however, I would say that it would struggle to meet them out of the Five-seveN handgun and by default Ruger’s new 5-7 handgun.

This is where things get interesting. Yes, the 5.7x28mm ammunition was designed to be shot out of a 10″ barrel, but .22 Magnum was designed to be shot out of 16-24″ barrels… so, how does .22 Magnum stack up when used in a handgun?


Unfortunately there aren’t a lot of ballistics gel tests done for .22 Magnum out of handguns, the good ones that do exist are typically out of snub nose revolvers with barrel length’s that are considerably shorter than the FN Five-seveN. We’ll work with what we got though so we can make some determinations.

Image From LuckyGunner

Above what you’re seeing are the terminal ballistics for .22 Magnum shot out of a Ruger LCR (1.87″ barrel). Yes, it’s only a two shot group, but Shooting The Bull did a video (found here) with the North American Arms Mini-Mag. The NAA Mini-Mag only has a 1.125″ long barrel, yet from the five shots it got 13-15.25″ of penetration.

These two tests combined, I think it’s reasonable to piece together that .22 Magnum has some consistency to it even though it’s being shot out of sub 2″ barrels in the tests mentioned above. Whether it’s the lack of barrel length that’s acting as it’s saving grace and giving it the needed penetration or not, it’s getting it, even out of a 1.125″ barrel which is impressive to say the least (at least to me).

How does the 5.7x28mm stack up here?

Out of a rifle, it definitely surpasses the capabilities of .22WMR without a doubt. Out of a handgun? Well… it’s a two sided answer. The wound channels on the 5.7x28mm are better than the .22WMR wound channels in terms of width in the gel, but, it isn’t getting the same levels of penetration as the .22WMR which the FBI’s minimum requirement is 12″ of penetration…so… it’s a coin toss on which is better?

Side Note: It’s entirely possible that with even an extra inch of barrel out of a handgun that .22WMR becomes trash when compared to 5.7x28mm out of the Five-seveN. It’s real hard to say due to the lack of testing I’ve been able to find for both cartridges.

The 5.7x28mm cartridge does have a couple things going for it though over .22WMR.
– It’s a reloader’s cartridge through and through.
– It’s centerfire which is more reliable than rimfire.
– Because it’s rimless, it can’t get rimlocked in the magazine

Are those advantages worth the additional cost? I’d say it’s entirely user dependent, especially with how reliable quality .22 Magnum has become.


The biggest question to answer here, is 5.7x28mm viable for self-defense?

Yes, with the right round choice it can/should achieve adequate penetration while producing “good enough” permanent wound channels.

Is it optimal in any way, shape, or form?

I would say no unless you’re a reloader.

The cost per round is too high, especially considering the alternatives in both the PDW world and the handgun world. .300BLK and 5.56, even with subsonic loads, are going to do better damage even against soft armor than 5.7x28mm. As far as handguns go, the cost for plinking ammunition is the same as shooting the highest quality defensive ammunition for any of the primary duty calibers…calibers that have a good track record, have a lot of testing behind them, and have proven themselves.


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