Defensive Shotgun Patterning: Deconstructing the one inch per yard myth
 

Interesting article about what shotgun patterns spread per yard after exiting the barrel.

The old adage predicts, if a shooter is 10 yards from his target, the pattern will be 10″ and 15″ at 15 yards and so on.

Typically, this discussion is framed around defensive use of the shotgun with a relatively short 18-20″ barrel and some sort of defensive load like the 00 buck.

To test this theory they used a series of 5-barrels and Winchester Super-X 105-203-098, non-plated full power, 1325 fps, 2 3/4″ buckshot.

They selected this load because they found that the tactical and reduced recoil loads on the market pattern tighter then non premium buck and thought this load would provide a better representation of what the typical defensive shotgun owner would encounter.

The test barrels were all 18″ in length and described below:

1. Rifleshooter.com back bored & lengthened forcing cone barrel (back bored until reamer was flush with muzzle)

2. Vang Comp Custom Barrel

3. Remington Factory Improved Cylinder

4. Remington Factory Cylinder

5. Rifleshooter.com back bored and forcing cone lengthened 2″ from muzzle


They measured the extreme spread of each pattern and recorded the results below in inches:

Barrel ................................ 7 yards ......... 15 yards ....... 20 yards ....... Avg spread per yard


Back Bored............................... 2" .............. 5 ¼" ............. 7" ................... .35”


Vang Comp............................. 1 ¾" .............. 7" .............. 7 ¼" ................ .36”


Remington IC........................... 5" .............. 10 7/8" ........ 11 ½" ............... .58”


Remington Cyl ........................ 3 ¼" ............ 9 1/8" .......... 12" .................. .60”


Back bored 2” from muzzle ....... 4 ¼" .......... 15 ¾" .......... 19 ¼" .............. .96”

They recommend the next time you wonder how your defensive shotgun patterns, take it out and shoot it with your favorite load at different distances.

Normally, they shoot 7, 15 and 20-yards, but they do shoot buck at shorter and longer ranges on occasion.

Or you can use Federal Flite Control buckshot and throw all of those numbers off. I think Hornady has something similar.

I've tested both the #1 and 00 buck out of my Mossberg 930 SPX. That's an 18.5" cylinder bore barrel.

Here's how the #1 buck did. Basically a wad-sized hole at 5, 10, & 15 yards and a 9 or 10" spread at 20.

http://i666.photobucket.com/albums/v...psf85c0727.jpg

That load looks pretty devastating in gelatin.

https://www.youtube.com/watch?v=JNb2uvezzx0

Thanks good info. I figured the improved cylinder would be better?

I've patterned my 28in barrel, but not my 18.5.

Shotshell for plaster birds....slugs for defense...no math really needed.

I agree and found something out I didn't think about.

Was able to run the Carbine run at a tactical day out at OSS.

Some of my slugs were spot on, some were low right, and some were off to the right.

You even need to find out the right slugs for your shotgun or you might be great at 5 yards but 25 with the shorter barrel installed.

Agreed..........I use homegrown slugs, non rifled barrels. One thing I do not do is depend on "shotshell spread".