Why You Shouldn’t Use .410 Shotshells for Defense

The Taurus Judge is not the first .410 caliber revolving shotgun-handgun hybrid, but it has been by far the most successful pistol of its kind. Despite being a heavy, bulky weapon that holds a mere 5 rounds, the Judge can be found in most well-stocked gun stores, and its suitability for personal protection has become a hotly debated topic on internet forums.

The signature capability of the .410 revolving handgun is its ability to use shot-filled shells, in marketing speak these guns are “pistols that fire shotgun rounds”. However, these sorts of bylines, while technically accurate, don’t accurately reflect the actual capabilities of the Judge or similar models of revolving handgun. I plan to cover handgun terminal effectiveness in a later post, but to start, a brief primer on both handgun and shotgun terminal effectiveness. Note that the following is highly generalized, there are exceptions, but I’m ignoring them for now.

Handguns fire single projectiles which may tumble or deform on impact. They cause damage through the direct crushing of tissue from the projectile itself. The shape and design of the projectile is as important, if not more important, than its caliber. A wadcutter .38 projectile, for example, with its flat, cylindrical shape, may cut tissue more cleanly and do more damage than a round-nosed FMJ .45 ACP projectile, despite being smaller caliber. The ultimate expression of this factor is modern JHP ammunition, which starts as a projectile shaped well for feeding in modern automatic handguns, but then expands to provide a flat, wide surface for the maximum tissue crushing effect.

Shotguns, on the other hand, shoot either a collection of round metallic projectiles, or a single short cylindrical slug. The slugs we’ll set aside for now, as they work similarly to very large pistol projectiles. Shot, the common term for a collection of round projectiles fired from a shotgun, is packed into a shotshell atop a wad. Larger shotshells like 12 gauge can shoot larger payloads of shot than smaller shotshells, like the .410 bore. This payload can vary from the same number of much larger projectiles, or many, many more projectiles of the same size. For defensive purposes, fewer projectiles of as large a size as is feasible is preferred versus a greater number of smaller projectiles, due to the need for adequate sectional density to penetrate a target.

This brings us to sectional density. Commonly abbreviated “SD”, this is an extremely important factor to understand when discussing small arms projectiles, and it is essentially the measure of the mass of the projectile per square inch of frontal area. In small arms, it is calculated by a shortcut of weight of the projectile in pounds (grains divided by 7,000), divided by the diameter of the projectile in inches squared. So, doing a little math, we can calculate the SDs of some common projectiles, including a 9x19mm JHP before and after expansion, a 00 buck projectile, and the #4 birdshot projectile loaded in Federal’s 2.5″ .410 “Personal Defense” shotshell:

115 gr 9mm projectile (unexpanded): 115 gr / (0.355 in)^2 / 7000 gr/lb = 0.130 lb/in^2

115 gr 9mm projectile (expanded to 0.60″): 115 gr / (0.600 in)^2) / 7000 gr/lb = 0.046 lb/in^2

And we can get some relevant figures from Wikipedia’s handy lead shot data chart:

00 buckshot projectile: 53.8 gr / (0.330 in)^2 / 7000 gr/lb = 0.071 lb/in^2

#4 birdshot projectile: 3.3 gr / (0.130 in)^2 / 7000 gr/lb = 0.028 lb/in^2

Sectional density is one indicator of potential penetrative ability for a projectile (the other component is velocity – for most pistol projectiles the velocities are not different enough for it to be a major factor, but it still should be noted). We can see that the pistol caliber undergoes a change during expansion from about an 0.13 to 0.05 SD, while round 00 buckshot has about a 0.07 SD. In stark contrast, the #4 birdshot doesn’t even manage to reach 0.03. A round designed for personal defense must have enough velocity and sectional density (and tough enough construction) to penetrate deep enough into the body to create a fatal wound. A surface wound may be extremely painful to an individual, but that is often not enough of a deterrent to prevent a continued assault. The extremely light #4 birdshot projectile of the Federal .410 load does not have sufficient sectional density to penetrate deeply and reach the vital organs of a target, even with a completely flat shot against the torso without any barriers or angling.

Now, it is true that a mass of projectiles hitting a target all at once, as with a traditional shotgun, often can manage to penetrate more deeply than the sectional density and velocity of each pellet suggests, however by Federal law the Taurus Judge must have a rifled barrel or be declared an Any Other Weapon (AOW). This rifling imparts a spin to the shot column that separates the projectiles in flight via centrifugal force, preventing them from hitting the target as a concentrated mass, further exacerbating the already mediocre penetrative properties. To illustrate the differences between a true shotgun and a Taurus Judge “handgun firing shotgun rounds”, I have embedded two videos from the excellent channel Brassfetcher, showing gel tests of both the Judge’s Federal #4 birdshot load and a proper 12 gauge 00 buckshot load:

The differences are dramatic, with the buckshot penetrating about 16″ of gelatin. In contrast, the .410 #4 birdshot load penetrates only 4″ of gelatin without a heavy clothing layer. With the layer, it penetrates just 3.6″, scarcely enough to penetrate skin, and likely not enough to penetrate body fat on many humans. For further comparison, I have embedded another Brassfetcher video of a 115gr Magtech Gold JHP round impacting gel:

The projectile penetrated just shy of the end of the 10″ block, still well over twice as deep as the #4 shot, and expanded significantly (although no measurement is given).

There are loads designed to improve the Judge’s effectiveness beyond what the light birdshot loads are capable of. Federal also offers a four-ball 000 buck load which should have substantially better effectiveness which I would guess approximates, very roughly, four light .32 ACP FMJ training loads in terminal effect; not a comforting idea, but the load is probably actually lethal as opposed to the substantially sublethal birdshot option. Winchester has taken the concept a step further, offering its Supreme Elite PDX1 “hockey puck” or “pumpkin ball” load, which is three 68 grain 0.330″ caliber discs backed by twelve 8.5 grain 0.170″ cal BB pellets. The pellets, although somewhat bigger and heavier than #4 shot, probably aren’t contributing much to the lethality of that load, leaving it in the hands of the UFO-shaped discs – a dubious recipe for stopping power.

All of this is to say that the load the Judge was designed for – birdshot – doesn’t perform well enough to be acceptable as a self-defense round, and the other options – optimistically – only bring the Judge’s lethality in line with FMJ-firing semiautomatic handguns.

Source: www.thefirearmblog.com

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