Teflon coated bullets

Yesterday, the thought exercise “fight coming” post picked up a comment which was most likely 100% fictional, as it referenced non-existent “S&W teflon coated flak jacket penetrators.”

image courtesty recguns.com
image courtesty recguns.com

Now, nevermind for a moment that as near as I can tell, S&W never made a teflon coated round, let’s instead put a bullet in the entire grand myth of teflon coated rounds. First, we must examine the Hollywood myth around the teflon-coated rounds. Likely the best example of this is in one of my favorite movies, Lethal Weapon 3.

Now, the LW clip never calls the rounds out explicitly as being “Teflon-coated” but there are plenty of other mentions in media and even the news that do. So, the general assumption made is that Teflon coated bullets have better armor penetrative properties than standard jacketed ammunition because of the Teflon. This is only partly a mistake.

The Teflon coated bullets as we know them today were originally developed by a company called KTW, Inc. KTW did in fact set out to design a bullet that had better barrier penetration capabilities than the common service rounds in use in the 60s and 70s; they accomplished this by using a projectile constructed primarily of brass with a steel core. If that sounds familiar, good, because a considerable amount of former Communist Bloc rifle ammo uses a mild steel core to achieve better barrier penetration. Back to KTW, in their initial tests of the ammo, they found that the brass/steel bullets caused significant and rapid barrel well as well as poor accuracy. The alloy of the projectiles was too hard to properly engage the rifling of the barrels, hence the wear and accuracy issues.

This is how Teflon entered the picture; when used outside firearms applications, Polytetrafluoroethylene (Teflon) is valued for its low co-efficient of friction against other solids. This is why its used in non-stick cookware, as a lubricant, and numerous other commercial applications. When used with bullets, the coating of Teflon was specifically to help the bullet engage the rifling better and prevent the aggressive barrel wear caused by a naked projectile. It’s somewhat similar to the current practice of coating lead bullets with Molybdenum disulfide to prevent excess leading. These are commonly referred to as “moly-coated” bullets, and are quite popular with reloaders.

This leads us to the question of what happened to Teflon coated rounds? If the Teflon was only used to help the bullet engage the rifling and not wear out the barrel, why the big hubbub? Well, the first problem is that the rounds did actually work pretty well. Mind you, not because of the Teflon coating, but because a hardened brass/steel projectile is probably going to be pretty effective at going through stuff a soft lead bullet won’t go through. Enter the mainstream media; in 1992 or 1993, NBC News ran a hit piece on “cop killer” bullets, which in typical MSM fashion focused not on the projectile itself but rather on the Teflon coating. This bit of news reporting went 90s-viral, and “cop killer bullets” became a common talking point for the powerful anti-gun groups of the 1990s. The result was legislation in many states that explicitly bans Polytetrafluoroethylene/Teflon coatings on firearms projectiles.

Teflon coated bullets were an interesting side track on projectile development, but have fallen into the dustbin of history due to an inaccurate hit piece by the mainstream media. Now the world at large remembers Teflon coatings on bullets as some sort of magical round that zips through bullet proof vests because of the magic of Teflon.


  1. I think it was S&W’s and later Federal’s Nyclad Bullets that had everybody’s bowels in an uproar. These were the same people that were telling us those new plastic Glocks were a bad idea because they could slip passed metal detectors.

    1. I was the one that posted the fictional POST. S&W I believe only had 357 mag teflon coated bullets in the 70’s-80’s. But 20+ years in aircraft ind. taught me you can put teflon on any bullets if you have access to. Make some aluminum or Titanium bullets on a Machine Lathe. Not accurate at anything but nominal distances. But, WOW!. Twice the velocity and twice the fun. Dragnet said it “Only the Facts Ma’m, Only the Facts. I threw out all my shooting trophies years ago. They were corroding in my storage sheds for years. The only ones i kept was trap & skeet 97 out of 100 & Civilian/Police combat shooting in Hunt. Bch. CA. in 19 Who Cares.

      1. TWICE the velocity? At close to 3000fps won’t your .357 rounds overpenetrate pretty much, well, everything?

  2. Really great article…love when facts are put up against the media, plus I learned something new! Now if teflon bullets ever come up in conversation, I have something more than, “Physics doesn’t work that way” as a response.

  3. @Shawn Wesley Knight: Just shows that the producers of Ronin weren’t immune to Hollywood gun inaccuracies. I’m sure that line was put in there because it sounded cool and because it had been in the news lately, but not because they actually believed it. Even a great movie like Ronin is allowed a few mistakes.

    1. Which is funny because David Mamet wrote that movie and he is a long time competitive shooter and gun person. Of course he used a pseudonym so that might say something there.

    2. I doubt it’s that innocent Matt. I’ve seen TV programs pushing microstamping. They also have all ‘legally’ owned guns registered and easily traced. Big laugh. Like there are no second hand unregistered gun sales.

      1. Ronin is an anti-gun screed. That’s a good one. The main character says he loves 1911s. Of course you haven’t seen it, you’re talking from the currently fashionable paranoid world view.

        1. I actually wasn’t making a “Ronan” comment. FYI I love Ronan. Only pointing out that anti-gun comments aren’t ‘innocent’. Ever notice how many action/fiction shows have guns as useless. It’s NEVER an accident.

          1. I don’t disagree with you. I think the only remotely political statement in that movie is everyone’s complete disregard for the lives of innocent bystanders.

      2. On a related note, a show I watch called The Glades, which is about a detective from the FDLE (FL Department of Law Enforcement) went out of its way last night to point out that in the state of Florida, guns are not required to be registered. They didn’t do it in a “negative” way; I’d call it neutral. But it was a noticeable change from most cop shows when they say “the gun is unregistered” and then lock eyes because possession of an unregistered firearm is meaningful and something only a bad guy would do.

  4. I remember the contriversy well. They were quickly relegated to police/military only. One local dealer sold them one at a time for $2 each as collecters ammo.. This was in the early 70s when ammo was 10-25 cents a round. This whole “cop killer” bullet was/is B.S.! In the above mentioned ‘Lethal Weapon’ the C.K. (Cop Killer) rounds were shown not only going through body armor like a hot knife through butter, but doing massively more damage to flesh than any known handgun ammo. This is still pushed by a PC media. Shows like NCIS and Law & Order still and often purpetrate this. (The two NCIS shows are especially bad in the constant use of fully automatic weapons by bad guys. You might think there were thousands of them in the hands of bad guys.). Remember the Wnchester “Black Talon”? There was a media frenzy that they were ‘cop killers’. They too were quickly relegated to police only. Forgotten was the Remington “Golden Saber”. A bullet with the same capability’s but a more PC name. Now we have ‘ballistic tip ammo and they are not even considered ‘hollow points’. This lefty PC crap must be fought!

  5. I bought a lot of Winchester 10mm silver tips when i got my first Glock because there wern’t any cases for reloads for about a year after that until starr brass popped up at the gun shows. I still haven’t shot any of those yet. Looking at a box of them right now 1 of 100 @ 7.95 per box of 20. Don’t make them any more?, Box of 20 or 50 would be how much now?. Only place I could find them was at L. B. CA. Police and Uniform Supply. Go figure?. Since then use starr brass new, Hornady XTP’S hollow pt and Hornady and speer fmj’s flat nose 170 grns. Since when was a box of handgun ammo only 20 rnds? Hmmm! sounds like a screwing to me.

  6. Contemporary articles and statements by Dr. Kopsch did report that Teflon added to the penetrating ability of the KTW ammunition. For example, Mason Williams in 1973:

    “Wishing to retain the tungsten alloy and yet design the bullets for use in handgun barrels, the next step was to reduce the dimensions of the bullets so that the tungsten alloy could not come into contact with the barrel lands. A stepped down area at the base further reduced the diameter of the tungsten alloy.

    In order to force the bullet to rotate and to allow the lands to dig into the projectile a copper jacket was cemented to the stepped down bullet base thus allowing the rear diameter of the bullet to solidly contact the barrel grooves.

    With this design, all the advantages of the tungsten alloy were retained and yet thousands of rounds could be fired through a handgun barrel without excessive wear.

    …About this lime it was discovered that applying a coat of Teflon to the tungsten alloy core enabled the bullet to better penetrate metal. The Teflon did not affect interior ballistics. It was only effective at the target enabling the bullet to better “slip” through the metal barrier.

    …Based on these tests, KTW went to Kennametal Company of Latrobe, Pennsylvania for their sintered tungsten metal called “Kennertium”.

    [When] the price of tungsten alloy went to $1.00 per inch of 3/8″ diameter rod and it
    takes one inch of this rod to turn out a single bullet. …KTW then turned to steels and non-ferrous alloys which are considerably cheaper to buy and machine.”

    Oddly enough, Second Chance sold KTW ammunition in the 70’s.

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