Extreme Shock SRT: low powered .223 100 grain load

Extreme Shock have introduced a .223 Remington load called that the Short Ranged Tactical (SRT). It is very low powered producing just 745 ft. lbs. of muzzle energy, approximately 57% less energy than a 62 grain 5.56mm NATO round (SS109). This is about as much muzzle energy as a 10mm Auto round fired from a pistol.


Like all most of the Extreme Shock range, the bullets are made from compressed tungsten powder enclosed in a copper jacket. The round fragments when it hits a hard surface. As the name suggests this round is not intended for long range gun fights. It is a short range round suitable for self defense when over penetration of a standard 5.56mm or .223 Rem. round could have serious consequences. Extreme Shock says the round has enough energy to cycle a semi-automatic action.

The SRT’s 100 grain projectile is a frangible, lead-free design that will fragment on harder surfaces that would typically cause a lead-core bullet to ricochet. This projectile consists of a compressed tungsten powder core that is encased in a high quality copper jacket, with a special DuPont coating to reduce the velocity. This all works to produce lower recoil and minimize muzzle flash, thus enhancing the ability to acquire second shot placement faster.

The MSRP is $41.27 for a 20 rounds. Not at all cheap.

Steve Johnson

Founder and Dictator-In-Chief of TFB. A passionate gun owner, a shooting enthusiast and totally tacti-uncool. Favorite first date location: any gun range. Steve can be contacted here.


  • Matt Groom

    Being a 100 grain load, I’m sure that it tumbles and fragments very easily, especially considering most people will be shooting these out of a 1:9 twist that will effectively be launching them sideways.

    Also, 745 ft/lbs? WTF? People have been telling me for years and years that my trusty little M1 Carbine is underpowered and can’t be considered for serious defensive work (which always causes me to scoff and guffaw loudly) because it only produces 1050 ft./lbs with my favorite cast bullet reload. I’ve never shot anything that drew a pulse with it, but I’m sure it would do the trick admirably, and it will definitely have better range and accuracy than this new load will.

  • Mu

    The “special DuPont coating to reduce velocity” is an odd one. The one coating DuPont is well known for is Teflon, and that usually gives you increased velocity. The one thing I can think off is an oversized Teflon coating that initially hold the bullet back, allowing more gas pressure to build up to operate AR-15 type rifles. Since Teflon is soft it would rapidly flow along the bullet and allow for normal passage of the bullet in later stages of the firing. If this is true, I’d be wondering about gumming up my rifling with Teflon and risking barrel damage due to the oil shot phenomenon upon switching back to regular rounds.

    • Mu, I also wondered about that coating. Maybe you are right, it is slightly oversized.

  • Tony

    I was going to ask about the wound ballistics properties of this round but then I found their web site. Never mind.

    Good grief, that is some hysterically funny marketing those guys have! 😀 Makes one ever so slightly doubt the validity of their claims… 😛

  • JJG

    .223 already penetrates less than 9mm fired from a carbine, so I don’t really see the point of this. It makes an already dumb idea (using frangibles for defense) even worse.

  • Important question: What barrel twist rate is required to stabilize these?

    • Emptormaven, I wondered about that myself. I am not sure how to calculate it. I am not sure how to apply the standard formula for calculating optimal twist length, the Greenhill formula, to a tungsten bullet. Also, you need the bullet length to use the formula, and I have no idea what that would be given that it is tungsten and a very odd weight for the caliber.

  • solomon

    I know the special ops community likes to have a tool in the tool box for every situation but this is getting ridiculous. If you’re at close range why not use a handgun? And if you do have these loaded and your target is not “close range” then what then? Seems like an overpriced – limited round to me. Can anyone name a real use for this?

  • Matt Groom

    The construction of the bullet is only important so long as it determines its mass, which dictates its pressure. The rate of twist necessary to stabilize a round is entirely dependent on the length of the bullet, not on the bullet’s weight. That’s why the rate of twist is the same for .22 Long Rifle as it is for 9mm and .45ACP, 1:16, because the lengths are all the same.

    I estimate that the rate of twist necessary to stabilize a 100 grain, .224″ bullet would be 1:6.5 if it were lead, but being as it is made of Tungsten, it is probably shorter, since Tungsten is both lighter and more dense than lead. I might stabilize in a 1:9, which would make my previous comment about it tumbling moot (I did not notice the Tungsten construction), which would mean it would be terrible for home defense.

  • Brad

    Hmm… compressed tungsten powder bullets, it should be instantly frangible when hitting any resistance. And with a bullet weight of 100 grains, the cartridge would have to use a reduced charge to keep pressure within normal limits.

    Practical use? To me it seems very similar to a shotgun loaded with birdshot for home defense, which some people advocate. For indoor situations an M-4 type AR loaded with these cartridges would be a better choice than a typical handgun for limiting overpenetration and limiting downrange danger. Reduced flash and muzzle blast would be a welcome improvement too, especially for a .223 carbine with a plain muzzle.

    As for the cost, what are Glasers going for these days? Aren’t they even more expensive?

  • Burner

    I have used the 100 grain non-subsonic SRT rounds before in a 1X9 twist 16 inch barrel. At about 50-100 yards the bullet was well stabilized and was very accurate. I can’t speak for the penetration, especially in a subsonic 5.56 round. However oddly, I have been asked if the company made any subsonic rounds like this before, so apparently there is a market.

    I did some testing with their .45 ACP frangible rounds to recommend to some of my students needing ammo that won’t go through walls. The rounds may or may not kill the attacker but I can say that at least with the .45 ACP AFR round, the bad guy will NOT be fighting once shot. Seeing the devastation in the target compared to some bad Hollow points or FMJs was amazing.

  • Mu

    Glaser blue start at $2 a round, so it looks competitive price wise.

  • Tony

    “I know the special ops community likes to have a tool in the tool box for every situation”

    I highly doubt the special ops community has anything to do with the products of this company – outside of their marketing departments wet dreams, that is. 😉

  • FWIW: NSWC-Crane bought $654 worth last May. Clearly, that would only allow for a limited evaluation.

    The military has tested other 100gr 5.56mm projectiles before. PRL’s powdered tungsten core projectiles performed very well in gel tests, but their rainbow trajectory was a serious turnoff. In a different test, accuracy was reportedly quite miserable with experimental projectiles which used the jacket of a M856 Tracer projectile filled completely with lead (no steel insert or tracer compound).

    Before they introduced the Extreme Shock line, Mullins Ammunition was a fan of super-heavyweight conventional bullets. He offered loaded ammunition in .45 ACP and .40 S&W with 250gr and 200gr JHP, respectively.

    • I guess it is only good for very close quarter with a rainbow trajectory.

  • matt

    how much do you wot for your 223 100 grains bullt i have a 223 rem. thank you matt if you wot to call me at 972 423 1474 tank you matt

  • russell

    i purchased 60 rnds a year ago. the first box of 20 three rnds failed to exit my 11.5″ bbl.icalled the mfgr the response was nil,no concern.very bad.i used a puller to find why. no powder in some of remaining rnds