Mad Gun Science: Is Birdshot Effective for Home Defense?

   03.18.15

We gun folk are exceptionally guilty of repeating hearsay and assuming it’s truth. You know how it works. If some hypothetical scenario gets repeated enough, it becomes the truth.

This week’s Mad Gun Science experiment has to do with the idea of using birdshot for home defense. This one has two “hearsay” truths.

Birdshot is effective at short range because the shot acts like one big projectile before it has a chance to spread out too much.

Birdshot is not effective for home defense because the small and light pellets won’t penetrate enough to stop a determined home invader.

Rather than discuss the theoretical merits of each argument, I decided to go shoot some stuff with birdshot at very short ranges. For ammo, I elected to use a broad range of what might be considered birdshot. This is not any test of specific brands or loads of shot shells, just what I had on hand that represented a cross section of sizes of birdshot pellets. Oh, all of these are 12 gauge loads.

Remington Sportsman Hi-Speed Steel #1, 1 ¼ oz, 3”, 1,400 fps

Remington Premier Hevi-Shot Buffered Waterfowl, #4, 1 ¼ oz, 2 ¾”, 1,325 fps

Federal Target Load, # 7 ½, 1 ⅛ oz, 2 ¾”, 1,145 fps

Winchester Universal, #8, 1 ⅛ oz, 2 ¾”, 1,200 fps

For the gun, I chose to use my Beretta 1301 Tactical Shotgun. It’s a perfect home defense gun and features an 18” cylinder bore barrel. Since the test gun is un-choked, you might assume slightly better results if you use a choke to narrow your pattern even more.

Group size

Since the theory is kinda based on the concept of the shot acting more like a solid projectile at short range, I figured it was a good idea to measure pattern sizes before I started blowing things to pieces.

Here’s what I found.

Birdshot pattern sizes

Shooting hard objects

Since I couldn’t find anyone willing to get blasted with birdshot, I found some substitute materials in my garage. While it’s obvious that buckshot will go through just about anything, especially at short range, I wasn’t really sure at what distance small birdshot would start to lose effectiveness in terms of the “mass of shot” theory.

I had a good bit of ⅞” and ½” plywood collecting dust, so I nailed some to a target stand and shot it with all four shot sizes from both 10 and 15 foot ranges.

At a range of 10 feet, all shot sizes made dramatic holes in this 7/8" thick plywood.
At a range of 10 feet, all shot sizes made dramatic holes in this 7/8″ thick plywood.

From 10 feet, all four pellet sizes blew single large holes right through a single sheet of ⅞” plywood, as the “mass of pellets at short range” theory indicated. Not being satisfied with success, I broke out some of the ½” plywood sheets and put two of them out, one behind the other and tried the “common” #7 ½ shot. Again, the shot went right through both sheets and left a single large hole.

At a range of 10 feet, even #7 1/2  birdshot penetrated (2) 1/2" thick pieces of plywood.
At a range of 10 feet, even #7 1/2 birdshot penetrated (2) 1/2″ thick pieces of plywood.

From 15 feet away, I started to see the effects of a spreading shot pattern. When fired at the single ⅞” plywood, only the #1 shot cooking along at 1,400 feet per second made a single ragged hole. The #4 shot did penetrate the plywood, sort of. If I had to guess, I’d say maybe ⅓ of the shot pellets made it through. The #7 ½ and #8 shot did not penetrate the ⅞” plywood sheet. Wanting to replicate the common #7 ½ shot against the two sheets of ½” plywood from the 10 foot test, I fired away from 15 feet. The #7 ½ shot made a large single hole through the first ½” plywood sheet, but was stopped by the second. Range matters with bird shot, even a difference of just five feet.

Just 5 feet farther away, the #7 1/2  birdshot started to run out of gas. It went through the first 1/2" board, but not the second.
Just 5 feet farther away, the #7 1/2 birdshot started to run out of gas. It went through the first 1/2″ board, but not the second.

Ballistic gelatin

So shooting at boards showed that there is a benefit to the “closely packed mass of pellets” theory. Now, I wanted to see how things worked at our two test distances with gelatin blocks. I used to 6x6x16” Clear Ballistics gel blocks, one set up at 10 feet, and the other set up at 15 feet. Since the whole idea of this experiment is to test the effectiveness of birdshot, I elected to use 7 ½ size shot pellets. Those are the most commonly available “birdshot” loads. You’ll find those in the 100 round bulk packs at big box stores and most any ammo retailer.

The short answer to the jello test is that the gelatin blocks were most displeased. The longer answer is that birdshot pellets don’t penetrate ballistic gelatin very deeply. But that’s exactly why people like the idea of using birdshot for home defense – it won’t go through all of your walls and half way to Tuscaloosa.

This Ballistic Gelatin block was most unhappy. Even the wad penetrated about an inch and a half.
This Ballistic Gelatin block was most unhappy. Even the wad penetrated about an inch and a half.

From the 10 foot distance, most of the pellets penetrated about 4 ¾ inches. It’s an inexact science to measure precisely since the range of penetration of individual pellets was between three and seven inches. The wad penetrated about 1 ¼ inches.

From 15 feet, the bulk of the pellets penetrated about 4 inches with a range of two to six inches overall. The wad penetrated about 1 ¼ inches – about the same as the 10 foot gelatin block.

Once the pellets encounter continuous resistance, they start slowing down quickly. The four inch penetration depth was a bit of a surprise after seeing what the birdshot did to fairly tough plywood, but that’s why we’re testing this whole theory.

Conclusions

  1. I prefer not to be shot with any of these.
  2. Using birdshot against an attacker will likely make a huge mess.
  3. For this “solid mass of pellets” theory to hold up, you really need to be inside a range of 15 feet, preferably 10. The ability to blow large holes through plywood was far more consistent at 10 feet than 15. At 10 feet, shot size didn’t seem to matter a whole lot.
  4. As to effectiveness for home-defense, you have to make your own call. The short range performance was certainly devastating to plywood, but the gel tests showed nowhere near the level of penetration that a traditional handgun bullet would achieve.
  5. Blowing stuff up with shotguns is fun, even though I get strange looks at the range.

Tom McHale is the author of the Insanely Practical Guides book series that guides new and experienced shooters alike in a fun, approachable, and practical way. His books are available in print and eBook format on Amazon.

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