Alexander Arms’ Expanding 300 Blackout Subsonic Ammunition and Ulfberht Upgrades

    The 300 Blackout caliber has become the second most popular caliber for the AR-15, after the 5.56mm/.223 Remington caliber. What the 300 Blackout caliber especially excels in is firing subsonic ammunition to use in conjunction with a suppressor. However, subsonic 300 Blackout ammo is expensive and due to it’s slow subsonic velocity, most loads have rather unimpressive terminal ballistic performance. The most popular projectile used in subsonic 300 Blackout ammo is the 220 gr Sierra Matchking OTM. While it’s a good bullet but it costs 55 cents each in bulk and it doesn’t expand.

    For this reason, Alexander Arms had spend the last 2+ years to develop their own projectile for the subsonic 300 Blackout, which is significantly cheaper than the Sierra Matchking and it expands like a pistol hollow-point.



    A picture of the very early mock-ups of the Alexander Arms 300 Blackout from over 1.5 year ago. The projectiles in the images are clearly machined copper slugs and those are probably only used for testing magazine feed purpose.


    Alexander Arms 300 Blackout Subsonic Hollow point Ammo


    The production projectile with the conventional metal jacket construction. The Alexander Arms 300 Blackout Subsonic ammo will be available in both the hollow-point and FMJ versions. The projectile weight is 180 grain for both versions. Of course, the expanding hollow-point version is the more interesting of two. The MSRP for a box of 20 is $18.50 for the FMJ and $19 for the hollow-point. The cartridge case is likely new manufactured brass case from Hornady with the custom Alexander Arms head-stamp.


    The FMJ version of the Alexander Arms 300 Blackout Subsonic Ammo. The bullet tip is closed.

    Interestingly, Alexander Arms will be loading their subsonic 300 Blackout in two barrel length versions: one version for 10.5 inch short barrel, and the other for 16 inch standard barrel. Both will have the muzzle velocity of 1000 fps.


    In this video, Bill Alexander explains why he developed the new subsonic projectile:




    Also new from Alexander Arms is the new lightweight Ulfberht barrels. You can read about my first impression of the semi-automatic .338 Lapua Magnum rifle here.



    Close up of the new Ulfberht barrels from Alexander Arms: the carbon fiber wrapped version made by Proof Research, the coin dimpled version and the traditional heavy fluted version.


    Also new from Alexander Arms is the update version of the Ulfberht rifle that uses the above lightweight barrel, plus carbon fiber and titanium parts to reduce the weight by 15%. It also has a re-tuned gas system that making it even softer shooting than the original Ulfberht. Those are the M-Lok slots on the carbon fiber handguard.

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    Writer and gear editor with articles published in major gun publications. A five year combat veteran of the US Marine Corps, Tim is also part of Point & Shoot Media Works, a producer of photography, video and web media for the firearms and shooting sport industry. Tim’s direct contact: Tyan.TFB -at-