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Shooting Thoughts

There is a lot of information now available on the internet about shooting now days, but most of the information that I have developed through the years has been learned by trial and error. Years ago we did not have the internet so we had to go out and shoot at different yardage to develop our own ballistic tables for shooting long ranges.

Growing up in North Central Texas you seldom hear of anyone shooting an animal over 100 yards. In fact my ex-partner would never even think about taking a shot as far away as 100 yards. Most of his shots were 80 yards or less and most of the time he gut shot his intended target and we would spend hours trying to find and dispatch his wounded animal.

It was not until I started traveling to West Texas to do a little prairie dog shooting that I learned how to make really long shots. I was amazed to find out that I could shoot prairie dogs out to 300 yards with my ole model 700 BDL 30-06. With a little practice and a little time getting to know my weapon system and the ballistics of my ammunition that I was shooting, making long shots became second nature to me.

You read a lot on this website and others about home security, hunting and shooting, but rarely do you read much about getting to know your weapon system and the ballistics of the cartridge that you are shooting. In a shtf scenario this could become really important. First and foremost if you are really hungry and you can’t get any closure than 300 yards to an animal that you are hunting or an animal that you need to harvest in order to feed your family, then you need to have the knowledge and experience to make a killing shot. For security reasons this also should be important to all of us.

There are many good websites that you can look up the muzzle velocity of different cartridges shooting a variety of bullets. It is important to note that most of these published velocities are from bolt action rifles with a 24” barrel. If you rely on this information for an AR platform gun, I believe that you will find that your actual muzzle velocity is 300-400 feet per second slower than the published muzzle velocity. That is because most AR platforms are not shooting a 24” barrel and there is some amount of energy lost in forcing the bolt to open on an AR. As an example I have a 24” barrel on an ole AR and shooting one of my reloads I will measure with my chronograph a muzzle velocity 3100 feet per second. I can take this same ammunition and shoot it out of an M4 with a 16” barrel and the chronograph says the bullet velocity is about 2700 feet per second. So it appears to me that I am loosing about 50 feet per second with each inch of shorter barrel. So needless to say it’s important to know your weapon system and know the muzzle velocity of the bullets you are shooting out of that weapon system.

Many of these same websites you can enter your muzzle velocity of the bullet you are shooting, the weight of the bullet, the ballistic coefficient of the bullet, the elevation you are shooting at and the outside temperature, the height from center of scope to center of your barrel, and if you enter your Zero distance (the distance where your bullet hits the exact spot you are aiming at), it will give you a ballistic table or the trajectory of your bullet at different yardages. You can print this information out, laminate it and tape it to the side of your gun. Then all you have to do is know the distance. Some times you can guess this close enough, but many of us need to use a range finder to do this.

Some of the newer scopes out there all you have to do is know the distance and hold the corresponding cross hair on the target and pull the trigger, but there are many of us that don’t have or can afford some of these nice toys.

Another thing to consider is is the target moving. Seldom do you have an animal standing still just waiting for you to shoot it. Many times they are moving. It appears to me that most animals in our part of the world walk general around 4 feet a second. So the question is if an animal is walking, how much you have to lead that animal in order to get a terminal shot into it. Well that all depends on the muzzle velocity of your bullet and how far away the animal is. In the chart below you can see how much you need to lead an animal.

Approximate Leads For Hitting Moving Target
Target Travel is Perpendicular to Bullet Path
Lead is from Center of Intended Hit Zone
2900 Muzzle Velocity

Traveling 4 feet per second Traveling 22 feet per second
Yards Amount of Lead in Feet Amount of Lead in Feet

100 .414 2.27
150 .621 3.41
200 .827 4.55
250 1.03 5.69
300 1.24 6.83
350 1.45 7.96
400 1.66 9.10
450 1.86 10.24

From this chart you can see that if an animal is moving approximate 4 feet per second in a direction perpendicular to your bullet flight and he is 300 yards away, you will need to lead this animal 1.24 feet in front of the intended target in order to make a kill shot. And it is important to note that this for a bullet traveling with a muzzle velocity of 2900 feet per second. As the bullet gets further away it slows down, so you might have to make a minor adjustment with a little additional lead, but it want be that much.

You can also see the relation ship of speed of the moving target and how much correction you have to make. If the same animal is running at approximately 22 feet per second, you would have to lead this same animal 6.83 feet in order to get the bullet to hit the intended target.

Another thing that affects bullet flight is if you are shooting level to the ground or shoot uphill or down hill. Gravity has less affect on bullet flight if you are shooing up or down hill. The chart below gives you and idea on how this works. The formulas for developing this data was established by Major John L. Plaster, USAR (ret).

Cal. 308 Sighted In 100 YDS
165 Grain BC .447 MV 2840

Distance 100 150 200 250 300 350 400
Level Shot -1.02 -3.2 -6.9 -11.86 -18.4 -26.4
Degrees Up or Down
5 -1.15 -3.27 -6.87 -11.8 -18.3 -26.3
10 -1.0 -3.2 -6.8 -11.7 -18.1 -26.0
15 -.98 -3.17 -6.6 -11.4 -17.7 -25.5
20 -.95 -3.1 -6.5 -11.1 -17.3 -24.8
25 -.9 -2.9 -6.3 -10.7 -16.7 -24.0
30 -.88 -2.8 -5.9 -10.2 -15.9 -23.0
35 -.83 -2.7 -5.6 -9.7 -15.1 -21.6
40 -.78 -2.5 -5.3 -9.1 -14.1 -20.2
45 -.72 -2.3 -4.9 -8.4 -13.0 -18.7
50 -.65 -2.1 -4.4 -7.6 -11.8 -17.0
55 -.58 -1.8 -3.9 -6.8 -10.5 -15.2
60 -.51 -1.6 -3.4 -5.9 -9.2 -13.2

This chart was developed for a 308 that is sighted in at 100 yards and is shooting a 165 grain bullet with a ballistic coefficient of .447 and a muzzle velocity of 2840. It was also developed for shooting at an elevation of 9000 feet with a temperature of around 65 degrees F.

All you have to do is know the yardage and make adjustment to center of mass based on average height of animal or standard distance between ears or average size of head.

So using this chart you will see that if the gun is sighted in at 100 yards and you are shooting at a target that is 300 yards away, you will see that the bullet will hit -11.86” below the spot you are aiming. So if you want to hit center of the target you need to elevate the cross hairs approximately 11.86” above the intended point of impact.

Now let’s say you are sitting on a mountain top and trying to shoot an animal that is 300 yards away but it is approximately 45 degrees down hill from you. Where do you aim? In looking at the chart you will see 45 degrees on the left and if you follow it to the right to the point where the 300 yard mark intersects, you will see that the bullet drop will only be -8.4” below where you will be aiming. So instead of holding 11.86” like you would if shooting level to the horizon above your intended center of target, you should hold it only 8.4” above the intended center of target. It’s also important to note that this correlation is the same for shooting uphill or down hill. There is an old saying “aim low if you are shooting uphill or down hill”. This is because most people do not understand the affect of gravity on the bullet when shooting uphill or down hill. Most people shoot over their target when shooting uphill or down hill.

If you can spare the ammo, go out and give it a try. You might have to make few adjustments for your weapon system and bullets that you are shooting but it’s important to know what you can and cannot do.

In closing I want to say that I am no expert on this subject, but I want to share a few observations and thoughts. Hopefully they will help some one out one of the days.

Thanks for your time and I hope you enjoy.
 
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