The OTHER side of an accurate shot III

It is hard for a writer to resist when users ask for something.
It tells the writer that his efforts have not been in vain and that at least someone is finding them useful.
So, this week we will dedicate a little time to two subjects that are somehow inter-related: Squirrels and shooting at steep angles.

Follows the standard disclaimer: We will be talking about hunting, shooting and the killing of animals, if this bothers you STOP READING!

Pheww, sorry, but that needed to be done.

Squirrels in all their forms, families and varieties, are some of the most prevalent and pervasive mammals in the planet. You can find squirrels anywhere, except Antarctica (some naturalists will object to the use of the term squirrel for the Australian marsupials that fill the ecological niche, but for hunters'  "if it walks like a duck, quacks like a duck, swims like a duck, flies like a duck, sh__s like a duck; then it IS a duck" philosophy, we can stick to the general name applied morphologically to all creatures that are similar.
The impact of squirrels in the environment cannot be overlooked.
In some places they displace other squirrels (like the American Grey displacing the native British Red in the UK).
In others they alter the spreading processes of forests and have even stopped reforestation efforts by eating the tender bark of saplings, thereby "ringing" the tree into death.
In other places, still, the effect of the squirrels' voracious greed to store food has removed enough food from the environment as to endanger the health and well-being of songbird populations.

In SOME case, squirrels of the smaller varieties have had positive effects, making sure that there are passageways and burrows that other animals expand and use, sowing trees by hiding nuts where they later forget to look for them, and other instances.

OVERALL; the squirrels thrive near humans. Like their cousins, the rats (squirrels are rodents also), they are highly intelligent and adaptable. They will USE human activity and refuse whenever they can. Humans introduced the American Grey to the UK, and also the British Red to America. Now the non-native species is thriving to the detriment of the native ones on both sides of the Atlantic.

Squirrels have become lately, also a "Game" animal. You can now find them in some restaurants (at exorbitant prices), as well as farm raised. For the small farmer and land-owner, the squirrel can be another "cash crop".

As airgunners, squirrels are NATURAL targets for us. The size, human-closeness of their habitat, and the damages they cause to gardens, orchards, forests, bird nests and bird feeders, make them natural targets.

So, the perennial question: Where do you shoot them?

Perhaps this first simplified diagram will help us get the conversation started:

As you can see, from the broadside view, the brain is roughly located between eyes and ears, a little high on the head, and well protected by a relatively thick (for its size) skull.
The heart is located a little below the shoulders, but well above the elbow.
A hit to the shoulders area (especially with wadcutters, or with expanding pellets, will create enough damage as to render the squirrel dead in about 15 to 30 seconds. This may or may not be acceptable to you and to your conditions or situations.
In 30 seconds a ground squirrel can crawl back to the nearest hole to become an irretrievable, smelly, fly-generating carcass. Or it can drop down from the tree to be caught by almost any reasonably fit dog. Different circumstances, different results. Only YOU can decide whether a shot should be taken. Think before you shoot.

IF we want to comply with the Mike Pearson (MP) 10/10 rule, then we need to aim at the brain pan. The above diagram is lacking in some detail, so let's go to better and more academic diagrams, this next diagram shows the squirrel's nervous system:

As you can see, the brain, now that the squirrel is not fully broadsides, is not between eyes and ears, but above and behind the upper/rear corner of the eye. Do note that small protuberance to the rear of the brain, this is the cerebellum, and it is the spot you want to hit for an immediate lights off switch effect. So let's look at an even more detailed diagram of the brain, cerebellum and spinal chord stem:

As you can see, the cerebellum is located to the rear and, UNDER the cerebellum is the junction of the spinal chord and the brain, the spot I like to call the "medula oblongata". A shot precisely placed here will make the squirrel drop like a rock; sometimes, the squirrel will die so quickly that the claws will not even have time to let go. You will be left with a "fruit squirrel". Don't despair, allow some time for muscle relaxation and the "fruit" will fall from the tree. For these shots, since they are usually taken in the woods, at short ranges, I prefer using low powered airguns (0.177" cal. @ 12 ft-lbs) and a good wad-cutter pellet, preferably the heavy ones, like the RWS SuperMag.
If your rifle cannot shoot these pellets accurately, then try the H&N's Rifle Match 

Under some conditions and as long as your IMPACT speed can be above 650 fps, the expanding pellets (JSB's Predator, H&N Crow Mag, H&N Barracuda Hunter X )  may prove useful, especially for heart/lung shots. If we go to a detailed and more accurate circulatory system diagram, we would see this;

It is important to note that for these shots, you need to be ACUTELY AWARE of the shot angle. Not only because your trajectory will not be the same, but because the LOCATION of the organs changes in relation to external aimpoints with the spatial relation between squirrel and shooter.
So, from below and to the sides, the body side of the elbow MAY be a perfectly valid shot placement. From the front or broadside, that would be too low.
A good rule of thumb that has worked well for me has been to aim to the center mass of the cross-section of a plane that would cut the squirrel in half just behind the shoulders.

And here we come to the somewhat technical side of this week's post: HOW DO YOU AIM AT AN ANGLE?

The first and most common answer is "Aim low", but if we are ethical hunters and if we really want to comply with the MP 10/10 rule, then our target (REAL target, not the whole animal), is barely ½" round. So, low, yes, but ¿WHERE?

Hunting birds, squirrels and iguanas up in the jungle canopy of my native Mexico gave me a feeling that somehow, even the most "Scientific" approach was not working for airguns. And the reason is simple:
If you are a sniper, using a 0.50" BMG from atop the mountain range and you're shooting interdiction duty into a convoy of materiel winding its way along the road down in the valley, your shooting angle may be 20°, 30°, 40°, perhaps even more. BUT the distance you are shooting will be measured in HUNDREDS of meters (or yards). Whereas your scope's Line of Sight (LOS) can be, at most 10 cms (about 4") from boreline.
In our airguns, we routinely use LOS heights of 5  to 10 cms. (2" to 4") for distances measured in meters (or yards). The proportions are radically different!
The cosine rule, therefore, does NOT work in the airgun world.
You need to re-plot your trajectory for each "range" of angles you might encounter, if you want to be absolutely precise about it.
In my HUMBLE opinion, squirrel hunting is one of those instances when you want to be absolutely precise about it. The target is really small, and the animal enjoys a positive perception among the non-hunters. Any suffering will translate into a hideous perception of us and of hunting; and the outcome for hunting can be nothing less than negative. We owe it to future generations to be as precise, as surgical, as accurate, as we can be.

BUT; ¿How to achieve that?

Using ballistic programs.

Most airgun ballistic programs have the inclination datum as a variable, meaning you can plot several variations for the different angles.

How much can it change? well, let's use my favourite app: PP Calc. (obviously! LOL!)

Data from my WFTF D-54 shooting at 12 ft-lbs gives us this basic trajectory chart:

The little yellow circles are the groups shot for the basic calculations of the whole stuff. As you can see, the circles are almost perfectly bisected by the trajectory's parabola.

Now, let's move the muzzle 20° (up, or down, it does not matter):

The circles are still in the same spots, but the trajectory has been recalculated, At 35 meters (38 yards), where ordinarily I would have taken a correction UP, now I have to take a correction DOWN. Out to 20 meters (22 yards) there is little change, but beyond the apex at 25 meters (27 yards), change there is.

What about a steeper angle? Let's try 35°

Please note that the "near zero" has moved from 20 meters (22 yards) to 16½ meters (18 yards), that now shots between 21 and 35 meters (23 to 38 yards) require a ½ miliradian of DOWN correction (a full dot in my scope), and that my "far zero" has moved out to 45 meters (50 yards).

In FT the highest angle I've seen, and shot at, has been 45°: 

The little yellow circles are still where the shots "on the level" would impact, but the inclined trajectories beyond the first zero are different.
In the real world of jungle hunting much steeper angles are encountered, and measuring the real angle is one of the challenges, so we designed PP Calc to take a snapshot of the angle (in the reticule screen) and to input that angle automatically into the charts, graphs and tables.

Get to your shooting spot an hour in advance and check out the limbs where you have taken most of your shots, take a "picture" and record the incline. Then refer back to the tables, range card, or any other aiming aid you have devised.

If your gun is accurate and if YOU are an accurate shooter, there is absolutely no reason why you cannot take steeply inclined shots with great success!

Keep well, Hunt safely, and Shoot straight!






HM