Best Weapon/Ammo for Self-Defense In An Apartment?

VIDEO: "Here’s Why I Think Overpenetration Is Fudd Nonsense"

TFB TV (14  min.)

    My oldest son asked me what I thought would be the best firearm to use for self-defense in an apartment, concerned about penetration through a wall should he miss. 

    To be blunt, it is a pointless exercise to try and find a firearm/ammo combination that won't penetrate interior walls as you find inside an apartment or, in most cases, dividing one apartment from another. I lived in an apartment that had cinder block walls even between apartments, but the majority were just insulated interior walls: a couple sheets if gypsum board nailed to studs with a few inches of fiber glass insulation. All of the videos I've watched testing various types of ammunition have shown that anything that can penetrate deeply enough to be effective against a human attacker will easily punch through multiple interior walls or, even, exterior walls with siding or cladding. (See, e.g., this video testing various 12-gauge loads against simulated interior walls; this video testing penetration against various types of walls including a couple different type of shotgun loads against interior wall; this test of .22 LR from pistol and rifle; and this test of 9mm and .223 against drywall and then into ballistic gel). 

    The typical answer to this conundrum is to be careful of angles so that if you miss, the bullet will follow a safe (or safer) path: that is, following a path that is unlikely to hit an innocent, or striking structural features or furniture that will stop or significantly slow the bullet. But that answer does not really address the question of the ammunition or the weapon.

    What might be productive, however, would be to dismiss those weapons and ammunition that would overpenetrate a human target--i.e., cause a through and through wound--but still have enough power to go on an penetrate a wall or injure someone behind the attacker.  That would mean looking at weapon and ammo combinations that would not exceed the FBI recommended maximum penetration in ballistic gelatin of 18 inches, shot from short distances of less than 25 feet--about the maximum you find in an apartment.

    Frankly, that is going to eliminate most any rifle or ammunition intended for hunting medium to large game whether or not you are using ammunition designed to expand on hitting a target. (See e.g., this video comparing .223 and .30-06 in ballistic gel and this video comparing low velocity versus standard velocity .30-06 loads in ballistic gel). 

    Conversely, the 5.56/.223, even in FMJ, performs well in ballistic tests without excessive overpenetration (see, e.g., this video testing Lake City M855 "Green tip" ammunition). However, standard 50 or 55 grain will be much safer if you are concerned about minimizing overpenetration. (See, e.g., this test of 55 grain versus 62 grain "Green Tip" against Paul Harrell's meat target). And these videos are pretty consistent with what I've seen over several years and dozens of videos: the "Green Tip" is more likely to overpenetrate than the 55 grain loads. On the other hand, bullets designed to expand on impact may essentially explode at these short distances (and high velocity) and not have adequate penetration to reach vital organs. So, with the 5.56/.223, the FMJ is probably the best choice for using inside an apartment.

    Although medium caliber bullets out of a full powered rifle like a .308 or .30-06 might not be suitable, shorter barrels and/or less powerful rounds may be acceptable depending on the bullet used. For instance, in the Stockton California school shooting in 1989, the shooter used an AK rifle shooting standard FMJ 7.62x39 that mostly produced through-and-through wounding and delayed yaw with the result that the rounds were both less lethal and over-penetrated. From what I've read, standard lead tip hunting bullet designs from the 7.62x39 just don't have the velocity to consistently expand and often will act like a FMJ bullet when striking a target. But there are designs specific for 7.62x39 that can offer good expansion without overpenetration at short distances (see, e.g., this test of 7.62x39mm Winchester 123gr Extreme Point in ballistic gel at short range; see also this .300AAC 110gr V-Max gel test shot from an 8-inch barrel, and this 300 Blackout 110 gr V-MAX Hornady BLACK Gel Test out of an 8.5-inch barrel).

    Most standard pistol cartridges using full metal jacket (FMJ) ammunition will also overpenetrate. (See, e.g., this video testing 115 grain and 124 grain FMJ 9x19mm ammo in bare gel; this video testing .45 ACP in ballistic gel and showing an old military training film showing penetration against wood blocks; and this video testing FMJ in 9mm, .38 Special, .40 S&W and .45 ACP). 

    Conversely, quality hollowpoint ammunition in pistol calibers will typically not overpenetrate. (See, e.g., this test of .45 ACP Gold Dot against bare and denim covered gel blocks; this comparison of 124 grain 9mm Gold Dot versus HST in bare gelatin; and this look at different hollow point bullets for 9mm and .45 ACP against Paul Harrell's meat targets). 

     Shotgun ammunition varies, but it appears that #4 Buck will not overpenetrate, and reduced power 00 Buckshot will not overpenetrate, but standard loads of 00 Buckshot may very well overpenetrate. (See, e.g., this test various shotgun loads and this video from Luckygunner on buckshot ammo). And, in fact, in the TFB TV video embedded at the top of the post, the 00 Buckshot not only blasted through the skinny perp and the interior wall, but also penetrated deeply into the ballistic block on the back of the interior wall.  

    Thus, if you are concerned about a danger to others in the same apartment or adjacent apartment through overpenetration, it appears that the best options are: FMJ 5.56/.223; an intermediate cartridge such as .300 BLK or 7.62x39 using thin walled, fast expanding bullets; standard defensive pistol rounds using a reliable hollow point bullet; or either a smaller, lightweight buckshot (such as #4) or reduced power loads of regular 00 Buckshot.