Sunday, June 24, 2012


I like shooting. I like throwing darts and other accuracy games also, but, there is something about shooting that just makes life better.

My favorite kind of shooting is called Bench resting. A person takes an accurate rifle, typically a bolt action, to a bench and then shoots targets at up to 1,000 yards. Morons will compare this to “sniping”, which it is not. Real snipers typically shoot from the prone position (laying down) and are typically camouflaged. I have hit targets at 700 yards and let me tell you, that is a pain in the ass. Theoretically if you can hit a target within 1” at 100 yards you can hit a 10” target at 1,000 yards. Yeah, right.

I ran into some Marine who was telling me he could shoot a guy in the head at 1,000 yards. Yeah, I will buy that for a dollar. Not. Lets talk shooting.

A 7.62 NATO round, or .308 Winchester if you prefer, travels about 3,600 feet per second. That means it takes a bullet about 0.83 seconds to reach a target at 1,000 yards, IF, it were to do something really amazing like ignore friction.

Let me explain this a little. A bullet is a projectile which takes advantage of the energy created by the rapid expansion of gases caused by a chemical reaction. This means that gun powder does not explode, it burns and as it burns it creates gas. The gas pushes the bullet through a tube into which a bunch of twisted grooves have been cut. The bullet is about the same size as the grooves so as the gas pushes the bullet through the barrel the bullet forms itself to the grooves and begins spinning. If the bullet were smaller than the grooves the gas would escape past the side of the bullet.

How long does the chemical reaction take to push the bullet out of the barrel? This is a good question. If the barrel is too short the bullet leaves the barrel while the gas is still expanding. If the bullet is too long the bullet is inside the barrel when the gas finishes expanding and the friction between the bullet and the barrel reduces the speed of the bullet. It would be great if the bullet left the barrel at exactly the point at which the gas quit expanding, but, slightly before is better than slightly after.

For a .308 Winchester this means a barrel of about 18 to 20 inches.

What happens once the bullet leaves the barrel? Several things. First, the bullet begins to drop at a rate of acceleration of thirty two feet per second (per second if you want to be finickey). That means in one second the bullet will drop 32 feet.

If you look at a ballistics chart the bullet looks like it will go up when it leaves the barrel. No chance of that ever happening, if it ever does call the Pope cause you just witnessed a miracle. When a bullet leaves the barrel it drops, almost as fast as a rock. Not quite as fast. Why not as fast? This guy named Bernoulli figured out that spinning objects create lift. In the case of a bullet the lift will not be enough to prevent the bullet from dropping, but, it will drop slightly slower than a rock.

In addition the shape of the bullet and the spinning creates friction between the air and the bullet so the bullet also begins losing speed as soon as it leaves the barrel. This means that while it might be going 3,600 feet per second at 20 yards it will not be going that fast at 500 yards or 1000 yards. How much does the bullet drop at 1000 yards? About 40 feet. It depends a lot on the bullet shape and the chemical reaction, but, 40 feet is a good estimate. The bullet drops about 7 feet at 500 yards. Targets between 100 yards and 500 yards are so much easier to hit than targets between 500 yards and 1000 yards.

On top of all that drop the longer a bullet is in the air the more effect the motion of the air has on it. This is called windage. Windage is the effect the wind has on the motion of the bullet. The slower the bullet is moving and the longer it is being affected by the wind the farther it moves.

When we fire machine guns we use what is called a “cone of fire”. Essentially this means that every bullet leaving the barrel of the machine gun is going to go somewhere within a very curved cone whose apex is at the end of the barrel. The base of the cone is on the ground somewhere and how big the base is depends on how far from the end of the barrel the base is measured.

Add the effect of the wind onto the cone of fire and things can get wild. See, the wind is not a consistent force. The wind may be blowing 5 mph near the shooter, 10mph 500 yards away and 3mph at 1000 yards. How is that for a wacky problem?

Okay, lets say you can put five bullets within a one inch circle in the center of a bulls eye at 100 yards. Can you hit a head sized target at 1000 yards? Maybe, probably not. Under perfect conditions those bullets might hit within 10” at 1000 yards. If you want to hit at 1,000 yards all the bullets at 100 yards better be in the same hole and that hole better be smaller than .5” diameter. Add wind and variables with the amount of energy generated by the chemical reaction and absorbed by the bullet and we have.....


See, not every case is exactly the same size, inside or outside. A case that is a little smaller on the outside with thicker material so it is way smaller on the inside will create a very different pressure profile than a larger case with thinner material and a larger interior space.

The first problem is the energy absorbed by the expansion of the case. The case expands to fill the chamber of the rifle. If the cartridge were the same size as the chamber the cartridge would not fit into the chamber. The cartridge has to be slightly smaller than the chamber so it expands when fired and it has to be extracted. In Vietnam the VC used cleaning rods to extract 7.62 NATO rounds from their Russian Mossin Nagant bolt action rifles. I won't get into why and don't try this at home kiddies.

So the variations in case size change the energy. What else? Diameter of the bullet.

A variation in diameter of 0.0001” can change the pressure distribution significantly. As pressure changes drop and windage change.

So hitting a target far away is really hard and that is why I like it. It is me challenging myself to become better. To understand the variables and achieve. This is pretty much why I do anything, but, that is me.

Lets look back at our Marine.

The government buys special super accurate ammunition that goes through more quality checks than your average automotive part, but, they cannot eliminate variability.

If you go to Sniper School they are going to tell you to keep your shots under 500 yards. Why? Because it is way easier to hit targets under 500 yards.

How to achieve the impossible, like moon missions and military operations?

Make the process idiot proof and then put incredibly talented people in the process. If you depend on the talent of the people the mission has failed. Depend on the idiot proof planning and execution of the mission. If you put excellent people in the process they can handle the unforeseen problems and achieve the goals. BUT! If those people have to use their exceptional skills the plan has failed and heads will roll.

If you have not been through Special Operation training you will not understand this idiot proof mission practice. If you have had some training and been through some execution then you know why it is important to put the best people into the most idiot proof plans.

I am not trying to take the wind out of special ops guys, put them down or whatever. They all know that what I am saying is true. People pretending to have been special ops trained think that the best people are chosen to improvise. Not true. The best people are chosen NOT to improvise unless it is necessary and to have the capability to know when the plan has failed and improvisation is key.

So some guy spouting about hitting targets at 1,000 yards and talking about how the plan always goes to shit and how he always has to improvise is just a wanna be, or someone who is hiding what they know with BS. Two ways to keep a secret, talk too much or don't talk at all. The former is easier for me. If people think its BS they won't be looking for a secret.

How about our Marine? Does the guy know how far a 7.62 NATO round drops at 1,000 yards? Has the person ever heard of Bernoulli? How do they handle variable wind conditions? “Variia what”?

I like shooting and I do it for fun. Yes, I can put 5 bullets in a circle about .5” at 100 yards with the right rifle. (and yes, the rifle is a big deal) Can I hit a target at 1,000 yards? Never have and don't think I can. Too much drop, too many variables. Could I be sure of hitting a person consistently at 500 yards? No.

There are lots of guys who are better shots than I am. Lots who are worse. I don't shoot to compete, I shoot to have fun and enjoy myself. If my experience shooting makes it possible to identify a guy bsing about how great a shot they are thats okay. If I choose to let the guy bs that is okay too.

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