I have always loved the story of Billy Dixon and his incredible fight stopping long range shot. I wrote about it last year in an Maximum Effective Range, you can read it here
https://americanfyrd.wordpress.com/2017/03/
Loose rounds has another good article about him here.
http://looserounds.com/2018/07/02/billy-dixon-adobe-walls-long-range-shot/
The three basic tasks of the rifleman are: Target Identification, Range Estimation, and Firing the Shot. Today, we will discuss range estimation; specifically, using the mil dot system.
The milliradian is a system of angular measurement which represents a 1 to 1000 ratio. In order to use milliradians for target ranging, we must accurately know the size of the object we are looking at, and how many milliradians it covers in our optic. If we know these two numbers, the math is simple. The formula is as follows:
Target size in meters x 1000 / measured milliradians = distance in meters
Most of us are familiar with the mil dot system as it is used in rifle scopes, but originally, the system was developed by the navy to calculate the distance to an enemy ship. It is therefore appropriate to use a naval example:
Captain America sees a Japanese battleship through his binoculars. Measuring it using the Mil Dot scale, he determines that it is 20 mills long. He knows that Yamato class battle ships are 256 M in length.
256 x 1000 / 20 = 12,800 meters
Captain America sets his guns for 12,800 meters, and engages the enemy ship.
In preparation for an upcoming unknown distance shoot that I will be hosting, I spent some time taking pictures through my rifle scope of a variety of targets at a variety of distances. This can serve as sort of textbook exercise for anyone wanting to gain more familiarity with the mil dot system.
Use the photos below to try for yourself. Answer key at the bottom.
If you prefer the English system, use this formula:
Target size in inches x 27.8 / milliradians = distance in yards.
The photos show three types of targets; IDPA, which are 46 cm w x 63 cm h cm, or 18.25″ x 24.75″ ( some of these are mounted horizontal in the photos),
PPC, 55.5 cm or 21.75″ wide (the blue part),
Appleseed Red Coat Target, 63 cm w x 46.5 cm h or 25″ x 46.5″
I originally planned to simply compare the distance calculations using milliradians, to the results from the laser range finder. However, this exercise showed the limitation of the laser range finder. I used a Leupold rx-100 rangefinder. Many of these targets simply could not be ranged at the distances I attempted, either because of interfering brush, or because the targets simply were too small to bounce a laser off of accurately.
It is also noteworthy that these targets were difficult to find, even though I knew where they were, and had placed bright- colored numbers on them. Target identification is the most difficult and most crucial of the rifleman’s tasks. If I can’t see it, I can’t shoot it (usually).
In some ways, this exercise is easier using the photos than peering through your scope, mostly because the image you are looking at is still, making it easy to count the number of mills that the target covers. This is much harder to do accurately when you have the movements of the rifle scope to contend with. On the other hand, you, sitting at your computer, have no sense of the terrain to let you know if your numbers are wildly wrong. When we hold the unknown distance shoot, all participants will be given a topographical map to aid their range estimation.
Finally, I did not get the camera mount on the scope perfect so some / most of these pictures appear canted. Also, the targets are sitting on un- level ground, so they cannot be milled straight across, but are at a slight angle. This will, of course, throw off the calculation; all par for the course.
Yellow 75 -87 M as ranged
PPC white 1 – this one ranged from 308 to 365 my calculation using mills is 347
Yellow 2- 156 M, 153 calculated
white 8- no laser reading, 252 calculated
Appleseed Redcoat- 662 M, 630 calculated
PPC through brush- no laser reading, 555M calculated
IDPA red- no laser reading 306M
IDPA blue Horizontal- no laser reading, 575
Green 1-253M, 242 calculated
Blue 12-177M, 180 calculated
This year, we extended the range out to 660 meters, a full hundred meters beyond the US military stated maximum effective range of the M4 carbine, and, incidentally, over two hundred beyond the same for the M14. The civilian imitations of these two rifles are the most popular weapon systems at my annual known distance shoot. My personal experience would lead me to agree with the Army assessment of the M4, but I think they grossly underestimated the M14. I would have given the M14 an honest 600 meters. Nevertheless, it got me thinking about maximum effective range, and the following are some musings.
Some of the keyboard commandos I know have watched the Magpul long-range precision rifle videos, and are now convinced that the .308 Win is a one mile cartridge. The point made by the instructor in the video is, I think, that with modern ballistic calculators, such a shot is possible. While the demonstration in the video is impressive, it is noteworthy that it appears that even with accurate measurement of range, wind, and a sophisticated ballistic computer, they are taking about six shots to make that one hit on steel at one mile. Secondly, the idea of making a 1600 yard shot with the 308 is not new. Here is a picture of the rear sight of the 1917 Enfield calibrated all the way out to 1600 (yes, it is not .308, but the ballistically similar 3006).
So does this mean the maximum effective range of the .308 is 1600 yards? How about this box of .22 shorts which, according to the box, have a range of 2500 meters?
Or the .50/90 Sharps buffalo gun that Billy Dixon used, during the Battle of Adobe Walls, to kill a Comanche chief at a surveyed nine- tenths of a mile?
These examples only show what is possible, not what is likely. Billy Dixon famously called his battle- ending fete a “scratch shot”, meaning he wasn’t sure he could do it again, or consistently. This brings us to the first requirement for determining the maximum effective range of a particular weapon system: The projectile has to reach the target in a reliable and predictable way. All bullets are affected by the same variables: gravity, wind, air density, spin drift, and coriolis effect. However, the more powerful the round (and by powerful, I mean how much kinetic energy does it possess), the less each of these affect the trajectory of the bullet. You can figure the wind drift for a .22 short the same way you do for a 300 Win mag, but if we say the drift for the first is 100 inches, and the second is 10, what would happen if your estimation of the wind speed was off by 10 percent? The 22 would be off 10 inches, and the 300 only 1. Then factor in all of the many variables that must be figured, and the potential for error accumulates. Those looking for a hard and fast rule will find this answer unsatisfying. More power is better, but how much is enough?
Those who love simple answers could look at the speed of sound. For a long time, the measure of the maximum effective range of a round was when it crossed from supersonic to subsonic. For reasons I don’t truly understand, a bullet’s trajectory is deflected in unpredictable ways when it drops below the speed of sound. It was also useful for reasons that have nothing to do with the speed of sound. In the days of stubby fat projectiles, most reached the back side of the sound barrier with plenty of energy to spare. The old NATO M80 147gr ball is a good example of old school bullet design. It drops below the speed of sound somewhere between 800 and 900 meters. At that speed, it still has just under 400 foot pounds of energy. That falls right in between 38 special and 9mm handgun energy levels, compared to the more modern 5.56 62gr bullet, which stays above the speed of sound till 700 meters, but only has 225 ft pounds of energy at that point. The energy is twice that of the 22 long rifle at the muzzle, to be sure, but pretty anemic.
This brings us to the second criteria for maximum effective range, which is that we want the bullet to have the desired impact on the target. If that target is a piece of paper, it only has to make a hole; if the target is a game animal, it needs to bring down the beast humanely; if the target is an enemy soldier, it needs end his ability to fight. The amount of energy to do either of the latter two is highly subjective, but it would seem reasonable to want a level of energy comparable to, or better than, a handgun.
Let’s look only at these two factors: staying above the speed of sound, and having at least 500 foot pounds of energy (45 acp and 357 magnum levels). The 7.62×39 would max out at 400 yards, with 522 foot pounds and 1388 feet per second. The .223 loaded with a 69 gr target bullet is down to 475 foot pounds and 1980 feet per second at that same distance. The .308 loaded with a 175 gr bullet is still above the sound barrier at 1000 yards, with 1200 feet per second velocity, and 560 foot pounds of energy.
In the beginning of this discussion, I said I believed the Army rating of the M4 at 550 meters to be about right, and 460 meters for the M14 to be very much too short. The numbers here would suggest that the M4 is even less capable than I would have guessed, and the M14 far more. The 7.62x 39 also far exceeded my expectations.
A final note: if Billy Dixon’s 425gr slug was still moving at 800 feet per second when it crawled out of the sky, it would have hit the Comanche chief with over 600 foot pounds of energy, more than enough to do the job.
Lately I have been thinking about the English long bow, yes I’ve been reading Bernard Cornwal again. It was truly an amazing weapon system combining power, accuracy and a very high rate of fire. You can usually get two of the three in a weapon, almost never all three. And it was cheap, the common peasant foot soldier could afford one, or even make his own. The only weapon that came close to it in outclassing it’s contemporaries in the power, accuracy and rate of fire was the M1 Garand and it was most definitely not cheap at $90 each in 1935, well over 3 months wages for a working man.
The long bow allowed England with it’s small population and impoverished economy (In the middle ages military might grew directly from the fertility of your soil) to dominate the battlefields of Europe.
Benjamin Franklin is said to have claimed that had the Americans had archers instead of riflemen the war would have been two years shorter. There is some merit in this line of thinking the range of the long bow and the Kentucky rifle are usually both cited as being about 300 yards, but when it comes to rate of fire they diverge. A rifleman might load and fire one shot per minute, while a longbow man fired 6.
This begs the question, why did the longbow go out of use so soon? No one seems to have a good answer. The only pitfall of the long bow was that it was a difficult weapon to master, requiring as many as ten years of training., and that it was punishing to the user, most having to retire in their thirties due to the damage done to their shoulders.
That as am argument for why it was abandoned makes no sense to me many weapon systems take a great deal of time to master, and even today you won’t find that many 30 year old infantry men on the battle field.
Some have argued that as peasants became wealthier they found more exciting things to do with their leisure than practicing, and competing in archery. This I also find hard to believe.
The best argument I think is that the nobility began to fear the common man armed with a cheap powerful weapon, one that could pierce the most expensive armor and at distances from 6 feet to 300 yards made the finest Damascus sword irrelevant. It is noteworthy that the Robin Hood legend of medieval insurrection centers on the long bow. Could pike men have forced the king to sign Magna Carta?
The people in power anxious to stay that way stopped promoting archery then began to discourage it out right.
As I stated earlier the only thing that comes close to the long bow in power, rate of fire and accuracy is the Garand, or rather it’s more modern variant the M14. Like the long bow it takes some time to master (thankfully not 10 years) and like the long bow it is with in the purchasing power of the working man. It cost less than a used car and unlike the car will last a lifetime.
Strangely the M14 has been abandoned by our military and thousands of them have been torched to keep them out of civilian hands.
american fyrd 