Allegiance Ammunition SilentStrike – Subsonic .223

Allegiance Ammunition has an interesting product, their SilentStrike .223. SilentStrike purports to be the worlds first fully functional sub-sonic .223 round. The bullet is 100 grains and in the video, Allegiance claims it will work in the AR-15, M4, and HK-416. Down a 16″ barrel, the round is reported to be at 975 fps velocity. This equates to about 200 ft/lbs, or about half of what 9mm typically provides in 4″ barrels.

No word if you need a specific length gas system to get the weapon functional like a 300 BLK.

Description from Allegiance Ammunition:

Whether a law enforcement or military team that needs astonishing stealth combined with maximum power and performance, SilentStrike delivers. SilentStrike fully functions in semi and full auto the M4, AR, weapons platform at a silent 975 fps. No modification to the weapon is needed. SilentStrike is currently produced in a lead free fragmenting Tungsten powder core. The fragmenting SilentStrike gives excellent results in soft tissue even at subsonic velocities.

Nathan S

One of TFB’s resident Jarheads, Nathan now works within the firearms industry. A consecutive Marine rifle and pistol expert, he enjoys local 3-gun, NFA, gunsmithing, MSR’s, & high-speed gear. Nathan has traveled to over 30 countries working with US DoD & foreign MoDs.

The above post is my opinion and does not reflect the views of any company or organization.


  • Bosch

    Get it now for the low low price of $2.38 per round!

  • Brody

    So its ballistically a .22lr in a .223 case.

    • anon

      If you shoot 100 grain tungsten powder cored, frangible .223 that will cycle an AR15 action, and is lead free while getting a similar amount of ft-lbs of energy to .380 while providing a greater amount of sectional density, then yes.

      In all reality, it is a cool little niche loading for trying to get a super quiet AR used for dispatching sentries, or squirrels without pissing off your neighbors.

      • JumpIf NotZero

        Yea, I’m calling bullshit on a 100gr 223 that stabilizes in even 1:7 enough that I’d want to risk down with can WHILE also running an unmodified gas system. We’ve seen this before from various companies, vaporware.

        • bobby

          1:7 will stabilize a 100 grain with that shape.

        • Ethan

          It should stabilize – most 300BLK barrels can stabilize up to 249grn bullets with a 1:7 twist.

          But reliability from a standard gas system? Yeah, I agree – not a chance. I made a long post above about it, but bottom line, no Last round hold open, no reliability.

          • JumpIf NotZero

            It has almost nothing to do with weight.

            It’s length and sectional density, so comparing to 30 cal is not a great idea.

          • Ethan

            And speed, and weight is a partial function of density. 🙂

          • JumpIf NotZero

            Don’t get smart with me boy. 🙂

            Cross sectional density, but all the same, silly round is silly.

          • Ethan

            On that we can most certainly agree, lol.

  • Blake

    100gr @ 975fps. hmm.. Well, if you really need to silence your AR, why not?

    But I think I’d go with a silenced carbine in 45ACP at about the same velocity packing more than twice as much lead (& not semi-auto, so quieter)…

    • Southpaw89

      De Lisle carbine!

      • Blake

        yeah, that’s my favorite 🙂

        But the fundamental concept is to use:

        – a powerful round that was designed from the beginning as subsonic (e.g. 45ACP is the obvious example, but you could also use cowboy-ish loads in 45 colt, 44sp, or any other big-bore pistol caliber that floats your boat as long as you keep it subsonic).

        – a weapon with a non-automatic closed action (no semi-auto, no revolvers) so that the action doesn’t make noise & no gasses escape without passing through the suppressor.

        Of course the De Lisle further enhances the suppression by using a progressively ported barrel so that not all the gasses escape at the same time or the same rate, and it has a huge honking can with tuned graduated baffles.

        However something like a conventionally-suppressed T/C single-shot handgun in one of the aforementioned calibers would already be pretty good & a lot less expensive.

    • bbmg

      Sectional density and bullet shape for the 45ACP is extremely poor compared so say a bullet of the same weight in a subsonic 300 Blackout loading, you’re much better off with that than a DeLisle – the smaller caliber is easier to suppress, and you get a flatter trajectory and shorter time of flight, which is critical with subsonic rounds.

      • Ethan

        *COUGH* 458SOCOM *COUGH*

  • Anonymoose

    Energy doesn’t wound.

    • JumpIf NotZero

      Pretty much. They may have been able to get people with this back in 2008, but with 300blk and a lot of valid 9mm carbine options, having subsonic 223 is just says “redneck giggle time” more than serious use anything.

      • M.M.D.C.

        “redneck giggle time”

        You say that like it’s a bad thing.

  • Dracon1201

    Hahahahahahahahahahaha! You funny man, you make overpriced .22 and sell it to us!

  • Joshz

    As we can see it did in fact not lock open after the last round. But we can do a cut and say that it did.

    • gunslinger

      saw that too. credibility -1

    • gunslinger

      but, why is that a thing? unless the notion is that there is less energy to sling the bold back far enough to have the mag follower engage the bolt lock? but if that’s the case, wouldn’t you not be able to cycle the gun?

      had a problem with an sks where the piston was fudged, and i couldn’t get the bolt back far enough to pick up the next round.

      • Ethan

        I’ve done a lot of sub-sonic AR loads and it goes something like this:

        Energy required to cycle the bolt back far enough to:
        Eject a spent casing: 4
        Pick up the next round and chamber it: 6
        Engage the hold open on a last round: 8

        Expected variation from round to round for commercial ammo: 3

        Almost any load will eject the case, and any load in roughly the right neighborhood will chamber the next round (with varying degrees of reliability), but only when there is consistent last round hold open can you consider that loading reliable enough for SD/Combat. That’s what is needed for a gun to run the way its supposed to – enough gas for LRHO (last round hold open).

        Typical off the shelf AR-15s are way over-gassed even beyond that – again for reliability’s sake. To have a round that doesn’t even reliably LRHO means it is in the bleeding edge of the reliability danger zone – OK for plinking (if you don’t like stoppage drills), but NOT a defensive round.

        For an in depth discussion, there are numerous threads over on the 300BLKTalk forum about reliable cycling.

  • sianmink

    100 grains, 976 fps, so basically it’s a .380 out of a 3″ barrel in energy but without all that diameter getting in the way. And I’d like to see that round disassembled, The bullet has to be over an inch long.

    I’m not sure what the purpose of this is.

    • Carlos U

      Hush dogs. I know because my ops are blacker than your ops.

      • MR

        ATF very interested in spending taxpayer moneys on this round. Eliminate dangerous poodle and chihuahua threat.

  • Madcap_Magician

    New from Allegiant! Win the caliber wars with the load that straddles both sides! By taking the “light” part of “fast and light” and combining it with the “slow” of “heavy and slow,” our research scientists have created a new paradigm of ammunition that everyone agrees is a terrible idea!

  • Southpaw89

    Can anyone tell me why the case appears to have a hexagonal neck? Never seen that before.

    • Giolli Joker

      As a wild guess, it could be to be able to recognize the brass as it might actually be machined from solid to give a small chamber for the limited powder inside, not to drop the pressure. There are already similar designs around (think bottleneck outside and cylindrical inside) for the same purpose. .. the hexagonal machining, if not just an optical effect, might just be a distinctive sign, though.

  • Rusty Shackleford

    Looks like the M862 Short Range round made with powdered tungsten instead of polymer.

  • Will P.

    I have a hard time believing it will be anywhere near stable even with a 1:7 twist. Cycling the action and everything else I can see as the 100gr projectile might give it enough pressure to do so. This is a niche thing though, because the bullet is not going to be effective for anything but punching paper past 75-100yrds at the most(which is all the mall ninjas want anyway). The .223/5.56 round has met it’s peak, it really met it a long time ago. When it comes to subsonic ammo speed has to be replaced with mass(generally speaking) and a 100gr projectile traveling at less than 1000fps is going to be about as effective as a .380acp which we know is on the lower end of “stopping power”, granted smaller frontal surface area will give it slightly better penetration, IF the round is actually stable and flying straight.

    • swede1986

      I bet it will stabilize. Rifling twist relates to the length of the projectile, and since this round uses Tungsten it will be shorter than a lead projectile of the same weight.

      • Will P.

        You have a good point on that. Assuming the core is 75% of the weight and the other 25% being the jacket. The tungsten would have a density of 75gr/2479.5 cu mm, where lead would be 75gr/4285.5 cu mm. So you could make a projectile that is roughly 58% the size of a lead cored projectile. That’s just running some rough numbers. Now you got me thinking, I need solid works so I can figure out a sectional density and the ballistic coefficient. Lol

      • Ethan

        A 300BLK barrel with a 1:7 twist will stabilize up to 249gr projectiles. I haven’t tried it but I’m willing to be a .100gr 224 projectile would also stabilize at that twist rate. Especially because its easier to stabilize at lower speeds.

    • Ethan

      Agreed. Also the 380ACP is only considered effective with expanding ammunition – something this bullet does not have. Another strike against it.

  • lucusloc

    What purpose does this serve? It is not like you are going to be sneaking up on and popping sentries without alerting their buddies. Shooting “silenced” weapons, even if they are subsonic, is still going to be like shouting at the guy. “HEY BUDDY, DON’T TELL YOUR BUDDIES I SHOT YOU!”

    If you really want a truly silent ranged weapon you are gong to have to go with a technology that does not function by way of a controlled explosion.

    • Ethan

      In terms of real world effectiveness it depends… speaking from experience a wet 9mm or 300BLK suppressor is quiet enough that while it may be heard, from 30yds away and out it will most likely not be recognized as a gunshot. Not because it can’t be heard if you’re listening for it, but because it’s quiet enough to blend in to the ambient sound range.

      Now lets move to 100yds away – a more realistic sentry/OP-LP distance. It likely wouldn’t cause you to look up from your newspaper.
      Now move into an urban setting where building make excellent sound traps, and it becomes the true ninja tool of blacky-black ops legend. 😛

  • noguncontrol

    as long as it can cycle the action and pierce soft body armor, i say yeah!!!
    BTW how quiet is this? quieter than .38 special from a levergun?

    • Ethan

      It won’t. Subsonic 300BLK ammo weighing 249grns doesn’t at these velocities. Penetration of Kevlar requires speed and hardness, but mostly speed. This may be hard, but it is also laughably slow.

  • Avid Fan

    You are not “operator” enough for this level of tacticool brilliance.

  • Dan

    video is from 2012! talk about necronews.

    also, they never sold any.

  • Geoffry K

    Didn’t sound subsonic to me from that video. Sounded like the normal supersonic crack I get from regular ammo with my silencer.

  • ksgunsmith

    this looks like the same manufacturer of the now defunct extreme shock ammo, gimmick then gimmick now

  • Notmyfirstrodeo

    I have 3 boxes of this exact same thing in my closet. It was once marketed by EXTREME SHOCK. My box says 223 100 ASP. The black coating is supposed to have something to do with slowing the round down the barrel. I have shot this in a 16″ with can and a 10.3ish with can. It is subsonic in neither. I have given a box or so away to people for their own testing but havent shot it in a while as at 100gr I was afraid my 1:7 wouldnt stabalize and I would have a baffle strike.

  • gwil

    Extreme Shock used to have the same round. I did some limited testing on it and it does a damn good job on groundhogs at about 50-75 meters. Additionally it functioned flawlessly in a 18″ spr with mid lenght gas system. I was running a yankee hills phantom qd can.

  • notsilent

    Wow!!! Those rounds were LOUD!!!