.300 AAC gel test: Sig 120 gr HT solid copper bullet

    .300 AAC Blackout Sig Sauer 120 gr HT

    .300 AAC Blackout Sig Sauer 120 gr HT


    The .300 AAC Blackout has enjoyed wild popularity over the last few years. Its subsonic performance is a big part of the marketing appeal, but there is little practical need for subsonic ammunition for most users. Subsonic ammo, no matter how cool, is still subsonic. At least so far as terminal effect is concered, 220 gr subsonic .300 AAC is no better than .45 Auto. In some ways, .45 Auto is better since there are projectiles for it that will actually expand when fired through heavy clothing. Now, before someone accuses me of saying that subsonic .300 AAC is useless or pulls out the worn out rejoinder of “I dare you to let me shoot ya with it,” I need to point out that no, it isn’t totally useless. Some folks have found it particularly well suited to discrete pest control and hunting. And no, I don’t want to be shot with it. I don’t want to be shot with a slingshot, either, but that doesn’t make it suitable for defense. Hey, subsonic .300 AAC is still fun. It’s okay to like it. Just because it isn’t practical doesn’t mean you can’t enjoy it.

    Supersonic, full power .300 AAC, on the other hand, does have a lot of potential for defensive use. The problem is that there isn’t nearly the array of choices as there is for many other calibers. Most of the projectiles were designed for use in .308 Win and many don’t expand or fragment reliably at .300 AAC velocity. That’s why it is encouraging to see a new offering in this category. The Sig 120 grain HT is intended for hunting, but looks to have real potential for defense.

    The numbers are outstanding.


    Expanded .300 AAC Sig 120 gr HT bullet

    Textbook expansion

    Five shot velocity average:

    2,093 fps
    2,153 fps
    2,126 fps
    2,130 fps
    2,122 fps
    Avg: 2,125 fps

    Penetration: 20.3″
    Neck: 1″
    TSC: 10″ X 3″
    Retained weight: 119.8 gr
    Max expansion: 0.645″
    Min expansion: 0.321″


    The velocity is very respectable for an 8″ barrel. The neck, that’s the distance traveled in gel before we see significant tissue upset, is very short. The temporary stretch cavity is a monster. The retained weight is essentially 100%. The recovered weight is within 0.2 grains of nominal, which is within the variation often seen in unfired projectiles. And, of course, the expansion was also incredible. This looks very much like the Barnes 110 gr TAC-TX in almost every way.

     .300 AAC Sig 120 gr HT temporary stretch cavity

    Monster temporary stretch cavity

    The one area that is less than ideal is the penetration. Like the TAC-TX, this bullet exceeds the 18″ max set by the FBI. It’s worth noting that this “over penetration” does not automatically disqualify it by FBI standards. It is simply deeper than needed. The fears about “over penetration” promoted by gun rag writers and pawn shop pontificators is largely overestimated in my humble opinion. Now, my opinion is worth exactly what you paid for it, but I have yet to hear of a single incident where a private citizen shot through a bad guy in a justified home defense shooting and harmed an innocent person. Yes, it happens from time to time with law enforcement officers. Yes, people have been harmed by missed shots. But to my knowledge, there has never been a case where the bullet passed through the bad guy and hit an innocent person. Of course, if you live in an apartment building you may be more concerned about the issue than if you live by yourself in a cabin on 40 acres. You have to decide for yourself what the risk level is.

    I’d like to see some more testing, especially barrier performance, and a larger sample size across a wide range of velocities, but at first glance, this load seems like a solid choice for defensive use.


    Andrew is a combat veteran of OEF and has performed hundreds of ballistic tests for his YouTube channel, The Chopping Block (https://www.youtube.com/user/chopinbloc). He is an avid firearm collector and competitor and lives with his family in Arizona. If you have any questions, you may email him at [email protected]