300 Blackout in a Howa Mini Action: Extreme Versatility in a Compact Package
Date: Sep 24 2026
my love for Shooters World SBR SOCOM Powder in the 300 Blackout.
a shorter-than-short action specifically designed
to work with cartridges such as 223 Remington,
300 Blackout and other cartridges that can
be housed in an AR-15.
The 300 Blackout is an interesting cartridge that predates its name; JD Jones originally developed it and called it the 300 Whisper. It is a unique cartridge because it can accommodate bullets from 100 grains to over 250 grains. This gives it the ability to use heavy bullets for subsonic loads and medium-weight bullets can duplicate 30-30 Winchester velocities. Lightweight varmint bullets make it an excellent self-defense cartridge for close-
for the 125-grain Nosler Ballistic Tip bullets can
be safely interchanged with the 125-grain Speer TNT.
quarters engagements, and military units have used it successfully to quietly dispatch sentries and clear compounds.
When it comes to the handloader, there are many lessons that can be gleaned from the 300 Blackout thanks to its extreme versatility. Here at LoadData.com and Handloader magazine, it is often used as a test cartridge for various bullets, as it is easily capable of duplicating long-range impact velocities when testing bullets. This is largely due to the medium- to fast-burning powders the 300 Blackout favors. Examples include Accurate No. 9 to Vihtavuori N-120.
minimal overtravel at 2 pounds, 8 ounces. The 3-position
safety is appreciated for hunting and field use in particular
while on horseback. You can also see the texture of the stock,
which provides some grip when working with gloved or wet hands.
In order to showcase this versatility while still offering new data proved to be a bit challenging, as there is already a wide range of excellent loads in LoadData.com. However, there is a slight shortage of cast bullet data, as well as data utilizing Shooters World powders. So, with these things in mind, the data was carefully calculated, components were gathered and I started out with high-quality Starline cases and Remington 71/2 primers (which at the time of this writing were on clearance on Midway USA’s website). These primers have been proven performers in the past and have shown in testing to be a little hotter than other primer options, making this a good fit for this project, as the 300 Blackout powders typically use ball or spherical powders. This means that they meter
and black web color/pattern, the wide forend
aids in riding bags while testing loads. The optic
is a Leupold VX3 4.5-14x50mm optic with
a Christmas tree reticle for holding over
which is quite common in the 300 Blackout.
extremely well, and when loading in bulk, a Redding Competition Model 10X powder measure works extremely well for the 300 Blackout, especially with the relatively small charge weights used for subsonic loads. Spherical powders also generally perform well with full cases and higher pressures. This is good if you want top-notch velocity with light- to medium-weight bullets; however, it can be problematic with subsonic loads, as they usually leave some space in the case, so careful powder selection is critical.
accuracy with a good load was more than acceptable.
This is a fun and inexpensive way to quietly plink with
subsonic bullets; it is also one that is commonly
used to eliminate unwanted pests around the property.
To help eliminate variables, an Area 419 Zero reloading press was used in conjunction with a Redding Deluxe Die set. To seat primers efficiently and consistently, an RCBS Automatic Priming Tool was used throughout, and all charge weights were weighed on an RCBS MatchMaster and were within .04 grains from case to case.
The test rig was a custom-built Howa Mini Action with an H-S Precision stock, 16-inch heavy contour barrel with a twist rate of 1:7 inches. It is topped off with a Leupold VX-3 4.5-14.5x 50mm, which has proven to be reliable as well as rugged. Due to the wide range of bullet weights and velocities they can be launched at, an
subsonic velocities and has proven to be a capable
and potent bullet in the 300 Blackout with
accuracy being more than acceptable given
the range limitations of subsonic loads.