Friday, December 20, 2013

Shooting from a Stand - Uphill and Downhill Holds

While driving down the road, I received a call from a friend in Missouri.  His first words were, "I need some technical support."  Since he is also a customer, I expected him to be at a person's home trying to fix their geothermal heat pump.  I was wrong.

Then I heard the words that no hunter wants to hear - "I lost my deer".  Immediately, I thought how horrible it would be to wound an animal and not be able to find it - especially for a first time hunter.  (I realize that eventually this can and may happen to any hunter, but it still would make a good hunter really feel bad.)  I just hated to hear that a wounded animal was not found, and even worse the thought that losing this deer may be the cause for this to be the one and only time this guy hunted.  I instantly went in to asking if he had focused on any landmarks, seen any blood, had he tracked it far, and the normal questions one would ask in this situation.  He told me that this evening, he had a beautiful big buck about 100 yards from his stand.  He said he shot and missed, and had done the SAME THING the night before, at the same distance from the same stand. Relieved that he said "shot and missed", as opposed to "lost" or shot and hit and not recovered, I shook off my usual pessimistic attitude and tried to help.

I discovered that he was hunting from a tree stand, looking down into a valley.  He was using a nice Winchester .270.  I asked again about the yardage, and he again stated -about- 100 yards.  He then went on to tell me his other buddy told him that he probably shot high because he was shooting from an elevated platform.  While his buddy was probably correct, my thoughts were more as to his distance estimate.  I explained that when you are elevated, the distance IS shorter than what you see (because of the angle - think triangles), but more than likely he guessed the distance as 100 yards when in fact it was probably between 50 and 100.  Things look farther when you are elevated than what they really are, especially when elevated and looking down into a valley.

This brought up the next question - "When shooting from an elevated location, do I need to aim low or high?".  My answer was to aim low.  He didn't ask, but I immediately thought to myself - why do I need to aim low?  What is the reason?  I had always been -told- to aim low when shooting form an elevated position, but never really thought much about it.

So, a little thinking while driving later, and I have the answer.  Trajectory.  Think about it - if you were to shoot exactly straight down, then the bullet would basically travel in a straight line.  Same with shooting straight up - the bullet would travel in a somewhat straight line.  Trajectory is the -curved- line of flight that the bullet travels.  Why is it curved?  Gravity.  When shooting level, your "line of sight" is level.  In other words, the line from your rear sight to your front sight (or scope) to your target is a straight line.  This is obviously the same if shooting up or down hill.  The trajectory is what matters.  When shooting on a level field, the bullet will be forced down by gravity.  If there was no compensation for the effects of gravity, your rifle would be sighted in only at the muzzle.  As the bullet leaves the muzzle, gravity forces it down.  To compensate, we sight in based on trajectory - the bullet travels along, rising at the muzzle and dropping back down (eventually) to the ground.  If there was no trajectory, all of your shots (unless at point blank range) would be low compared to your line of sight.  When we sight in a rifle, we have to remember that at closer ranges we will shoot high, and at longer ranges we will shoot low.  So what about uphill and downhill shooting?

Here's where most people get confused.  Your eye sees the line of sight.  At an uphill or downhill angle, your line of sight is longer than if you were standing on flat ground aiming at a target on the same level.  When you shoot up, you have just created a sort of triangle - you to the target, the target straight down, and from the target back to you are the three points of the triangle.  Not to bore you, but the line of sight is the "hypotenuse" of the triangle, and is always longer than the "base".  The base is the distance (on a level plain) from you to the target.  The hypotenuse is the line of sight up (or down) to the target.  Gravity does not change with your line of sight.

A target that looks (on the line of sight) to be 100 yards away, may in fact be only 40 or 50 yards away depending on the angle.  I'm not going into the Pythagorean Theorem here, but think about it - I'm in a stand, and my line of sight down to the target looks to be 100 yards.  If I go down to the base of my stand, the target appears to be much closer than 100 yards!  Remember that you are working with a triangle.  The angle is longer than the base, but gravity affects the bullet not over the line of sight, but over the actual distance.

My friend had just sighted his rifle in for dead-on at 150 yards.  I don't know why he picked 150 yards, but that's what he did.  He estimated the distance to be 100 yards (his LINE OF SIGHT!) and held his crosshairs on the kill zone.  To make matters worse, he was also shooting DOWN into a valley.  So, take an elevated stand, and shooting down into a valley - this adds up to shooting over the back of the deer.

If he were to draw a straight and level line, from the base of his stand straight out to the position of the deer, he would have found that the distance was probably only 40 yards!!!  His 270, sighted in for dead on at 150 yards, would have been almost 4" high at 40 yards.  Add to that 4" a little bit of "buck fever", and a new rifle, and a new scope, and not a lot of practice, and you have a missed deer.

This hits home especially for me.  I have gone to hunting exclusively with a handgun.  Lobbing a 44 Magnum at 1500 fps is like shooting a mortar.  High arcing trajectory, slow, big and heavy bullet.  Had I judged that same shot at 100 yards and held dead on, and sighted in at 150, I wouldn't have even been near hitting that deer.

Bottom line - if you are shooting up -OR- down hill, your line of sight is longer than the actual straight-line distance.  Aim low.

Better yet, PRACTICE shooting from a stand or elevated platform.  It definitely is different.

My friend went back to the range the next day, and found out that not only was his distance calculation off, but his scope was also off!  His scope had somehow moved (or likely never settled in) at around 1-2" high at 150 yards.  He then followed my advice and sighted in for dead-on at 100 yards.

I got a call the next day.  Deer down, found, and hanging in the garage.  He made a perfect shot on a beautiful deer.  Now he's looking forward to handgun season, armed with my advice on how to become horribly addicted to handgun hunting!!!