Some 5.7 Myths Busted

There’s a lot of talk in the gun world about the FN-Five-Seven. It’s regularly demonized as a cop killer. The folks at The Firearms Blog put some of the claims to the test with both the sporting ammunition, and with the S190 armor piercing ammunition that is not available to civilians. Their conclusion?

  • SS197 sporting ammunition from a handgun will not penetrate IIIA armor
  • SS190 armor piercing ammunition from a handgun will defeat soft body armor
  • 5.7 from a 16″ barrel will slice through body armor, but only FMJ will defeat stronger stuff
  • Surplus German helmets are really, really strong

Read the whole thing. Without the special SS190 armor piercing rounds, which are restricted to government and law enforcement only, the Five-Seven won’t penetrate soft body armor, and won’t penetrate tougher armor even with SS190 unless it’s fired from a rifle.

11 thoughts on “Some 5.7 Myths Busted”

  1. I wonder how the .22 Jet or .22 WMR performs. Both of those are available in handguns – although the .22 jet is very limited.

    1. Years ago a buddy bought a Remington .221 Fireball, which is a bolt action pistol based on a model 600 action. It had no problem punching thru 1/4″ of cold rolled steel at 50 yards, even with soft point ammo. Point is, there isn’t a problem with this gun, as it is way too big to hide easily.

      This is just another panic, same as the “undetectable” Glock from a few years ago. Something else to demonize.


  2. I wonder how standard, lead core, copper jacket, FMJ bullets would perform. Although, as far as I know, no one makes those for some reason.

    1. “I wonder how standard, lead core, copper jacket, FMJ bullets would perform.”

      I think that could be readily tested for a limited number of rounds by turning off the bases of standard 5.56 bullets, to match the weight of 5.7 bullets, and then loading them down to 5.7 velocities in a 5.56 rifle. Then, perform your tests. It would satisfy curiosity, and might indicate to a custom bullet maker whether it was worth having dies made to manufacture some. Doing so should not be a major capital outlay for someone already in the business. Or, for the home hobbyist, for that matter.

      1. That sounds like a good idea. It might be hard to find a five inch barrel to test it out of, though, if it’s in 5.56.

        1. No need — at least if I understand the tests. Just load the cartridges to give the desired velocity, regardless of barrel length, and fire them into the various test targets.

          What the .22 is chambered for also is unimportant, as long as it can produce the desired velocity. I imagine a .22 Hornet would work just fine.

        2. First, Wikipedia has a fairly comprehensive article about loadings for the 5.7.

          Some reservations about my own bullet-shortening idea are, that if you were going for weights much below maybe 40 grs. (especially 23 or 31 gr.) you might not be left with sufficient (or any!) bore diameter bearing surface, if you were shortening military ball 5.56mm bullets.

          However, if anyone wanted to play around with the idea, you could probably do it quickly and well by grabbing the bullets in a 7/32″ collet in a small bench lathe, maybe even a Unimat. Work out a stop in the collet so all you have to do is pop in the bullet until its tip presses against the stop, and leave the tool in same position in the cross-feed.

          I did that with 7.62 (.308) bullets, using a 5/16″ collet and it worked great, enabling the working of the bullets in a reasonable amount of time.

          One thing — don’t try that with anything but open based, fully-closed tip FMJ bullets. I have heard of FMJ bullets blowing the cores out of the jackets, when someone tried to make open-point hunting bullets out of military surplus. If a jacket stuck in the barrel it would likely be disaster at the next round.

      1. I won’t ask why you hope so, merely observe that that is an unwise thing to say in a public place like this.

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