300 Blackout Drywall Testing: What Happens if You Miss?

As a companion piece to our recent 300 Blackout 78 Grain “Close Quarters” Review, I also tested a multitude of common 300 Blackout bullets against simulated interior walls to see what might happen if they were fired inside a home – and missed their target completely.

One of the scary realities facing homeowners or renters who use firearms in self defense is the lawyer attached to every bullet they fire in self defense. The idea of hitting innocent family members or neighbors is horrifying, but possible and even likely if the wrong bullet is used. To further examine how 300 Blackout might perform if used in a home defense scenario, we set up three simulated interior walls made of 2x4s and 5/8″ standard drywall.

The test setup simulating three separate interior walls.
The test setup simulating three separate interior walls. The pictured results are actually from 5.45x39mm testing performed at the same time as the testing for this article.

The walls were separated from each other by 10′, which simulates interior rooms or hallways and gives the bullet time to fragment or tumble as it would in a real life scenario. Because interior walls typically do not have any sort of insulation, none was included in this test.

The Lineup

The following five types of ammunition were tested:

Lehigh Defense 300 Blackout 78 Grain “Close Quarters” Ammo
Lehigh Defense 300 Blackout 170 Grain Subsonic Controlled Fracturing Ammo
Double Tap DT Tactical 300 Blackout 110 Grain Barnes TTSX Ammo
Ozark Ordnance 300 Blackout 147 Grain FMJ Ammo
CORE Ordnance 300 Blackout 208 Grain Subsonic Ammo

The bullets from all of these cartridges were pulled to better illustrate the differences in their size, weight, and construction. The slight dents in the polymer tips were from hitting the end of the inertial puller.

Bullets pulled from our ammunition test lineup.


All of the different ammunition types were fired out of a 10.5″ barrel at a distance of 3′. In retrospect, confirmatory velocity testing should have been performed, but was not done so at the time. Velocities (except for the 78 grain bullet, which was measured in our review) should be taken as what the manufacturer states in their literature.

The 110 Grain Barnes TTSX bullets were accidentally labelled as 110 gr A-Max on the test walls.

Wall 1, Front Side


The bullets were grouped more or less together in the center of the first sheet of drywall.

Wall 1, Back Side


All of the bullets exited in one piece directly behind their initial points of impact on the front sheet of drywall.

Wall 2, Front Side


This is where things started to get interesting. The 78 grain Lehigh Defense bullet apparently had its aluminum nose separate from the brass base somewhere in the 10′ between the first and second walls, with both travelling sideways. The 147 grain FMJ bullet is also beginning to keyhole.

Wall 2, Back Side


Now things are starting to get messy. Compared to their initial impacts on the front of the first wall, the bullets (or their pieces) are starting to deviate from their initial trajectories. The 78 grain Lehigh Defense bullet is now very much in two pieces on two different paths, with the nose piece making an impressively clean outline as it travels sideways out the back of the second wall. The 147 grain FMJ bullet is also now turned completely sideways as it travels onward towards the third wall.

We didn’t realize it at the time, but the 208 grain A-Max subsonic bullet’s exit hole was part of the 110 grain Barnes TTSX bullet’s hole, and was overlooked in labeling.

Third 3, Front Side


Compared to their original trajectories, the bullets are now completely off course. Below is an overlay of the front of Wall 1 with the front of Wall 3.


The 170 grain Lehigh Defense subsonic bullet veered somewhere between Wall 2 and Wall 3 and hit the berm. The 147 grain bullet also veered and went through the drywall and 2×4 sideways.

The 147 grain bullet had enough energy left over after going through four sheets of 5/8″ drywall to penetrate the length of the 2×4 and keep going into the berm.


All of the bullets either penetrated all 6 sheets of drywall, went honey badger and ate up the test stand (147 grain FMJ, thanks for that), or veered off course and plowed into the berm. Despite using a wide range of bullet constructions, weights, and velocities, we achieved similar penetration from every bullet tested.

I know what you’re thinking…

“Of course all of the bullets penetrated! They’re .30 cal and heavy! Even the lightest bullet tested is one grain heavier than the heaviest of common 5.56mm loads. Maybe 300 Blackout is just a terrible choice for home defense!”

But let’s take a look at the test results one more time.

The Lehigh Defense 78 grain bullet split into two pieces by the time it struck Wall 2. From measurements taken in our review of that round, we know that the aluminum nose weighs between 22.1 and 22.3 grains, with the base coming in between 55.7 and 55.9 grains respectively. The nose piece didn’t have any trouble penetrating all of the wall segments on its own, and at only 22 grains and some change it weighs half of what even the lightest common 5.56mm bullets do. The base, weighing almost the same as very common bullets like XM193 and others, performed identically.

I would really have liked to have had a large block of 10% ballistics gel sitting behind the third wall to see how much energy these bullets had left after going through so many barriers, but such things are for those with more resources than this author. Suffice it to say, any stray bullet has the potential to wound or kill, and shot placement to the best of the shooter’s ability is always paramount. Rather than highlighting the importance of bullet selection, this experiment reinforces how critical effective and repeated training is to effective defensive firearm use.

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