Hunting at Maximum Point Blank Range (MPBR)

My story on shot placement seems to have stirred up a bit of thought provoking conversation about where a speedy bullet should go. Those opposed to my stance on neck shots cite the fact that the head and neck are constantly in motion vs. the mostly stationary chest cavity. I’ll certainly agree that the chest is a larger, more stable target. However, my opposition stems from the possibility of collateral damage to areas surrounding the heart and lungs. You could flinch and pierce the stomach, making for a long, painful death. Much like the 9 mm vs. .45 ACP debate, there will never be a clear winner.

Hopefully, the loyal readers of TTAG spend some time over at chuckhawks.com reading some of the top-notch articles they have in their database. I sometimes wander over to their corner of the internet when I want to burn a few hours and add a little knowledge to my brain.

I happened to be reading Randy Wakeman’s article on Ballistic Reticles only to find him reference “six inch kill point blank range” and find myself completely stumped. I hadn’t heard the term, but thanks to the wonders of high speed internet, I was able to find this article about Maximum Point Blank Range (MPBR).

Essentially, you isolate a vertical range that you find to be an acceptable margin of error. In the Wakerman article, Dave Affleck lists six inches. Affleck is a varmint hunter and therefore goes for 4 inches. Using a ballistic table like the one here, you isolate that vertical threshold, select the range your rifle is sighted at, and find your MPBR.

The theory: at any range less than MPBR, your bullet will fall within the vertical range that you have defined. If we’re going to take a shot, we might as well know what is safe and what is not.

I have one of the free ballistics calculators from Winchester on my iPhone and have taken some screen grabs to illustrate my point.

My ammo of choice: 95-grain 243 Winchester.

Condition Selection. Note the lack of wind and the 200 yard zero.

Data from the shots shows that I could have a five-inch threshold with a 250 yard MPBR. At any distance between zero and 250 yards, the bullet should fall within a five-inch vertical band. Assuming that the average whitetail has a vital zone in the chest of at least 12 inches, I should feel totally comfortable taking a shot at anything under 250 yards. This would allow a healthy margin for less than stable rests, “buck fever,” and the native accuracy limitations of my gun.

So what happens when the wind picks up? Quite a bit actually.

We can see that while the shot might deviate vertically from the point of aim by two inches at 240 yards, it will most likely deviate by more than four inches horizontally.

On a calm day, off a solid rest I should feel plenty comfortable going for a chest shot by lining up the crosshairs and squeezing the trigger. No need to hold high or low. Just squeeze the trigger and go collect my prize. However, when that wind starts picking up, my skill set needs to be exponentially better. I now have quite a bit more deviation to deal with.

My question to you is this. You find yourself with a shot like the one shown here atthe top of this post. Assume that is 275 yards and there is a 10 mph wind blowing from left to right. I’m shooting my trusty .243 with the load referenced above. I have a stable rest. Should I take the shot?