beyond a rather low point of about 7 to 8 degrees, the range will increase but at a very low rate. Generally, 8 degrees el- evation will deliver about 85 percent of maximum range. This clearly shows the danger of shooting without a backstop. (A bullet with a 2-mile range would travel 1.9 miles at 85 percent of maxi- mum range. This is 3,344 yards or 10,098 feet.) This is based on generalities and all bullets and loads will be different. There is no satisfactory formula
we become astronauts, none of us will ever be firing a gun in a vacuum, but the basic idea helps us to understand the real world. Because of air resistance, maxi-
mum range will be with the gun barrel elevated to an angle well below 45 de- grees. The maximum will normally be between 27 and 35 degrees. It usually will be closer to 31 degrees. As the bar- rel is raised higher than the optimum angle, say 31 degrees for example, the range will begin to shorten. Maximum efficiency is obtained at the lower angles. In many cases, as much as 65 percent of the maximum range can be obtained at an elevation as low as 5 degrees. The higher the barrel is raised
for working out maximum range in an atmosphere environment. Manufactur- er’s charts and military data are the best source for this information. Properly conducted field testing is within their capability, but it is not practical for the sportsman. Also pertinent are air density,
which affects range, as does a bullet’s weight, ballistic coefficient, velocity, etc. A method was given to determine
an approximate distance in a theoretical vacuum and most large caliber bullets at low muzzle velocity will travel from 14 percent to 20 percent of that distance. The lower the velocity and the higher the ballistic coefficient, the better the bullet will do compared to its no-air range. Lightweight hunting bullets at high velocity will attain only about 4 percent to 10 percent. Pistol bullets of lower velocity: 10 percent to 20 percent. Thin, less dense air from high
altitude or high temperature will also increase range. Air resistance can never
be forgotten. After all, air resistance is the factor that lowers the elevation for maximum range from 45 degrees down to an average of 31 degrees. At an eleva- tion of 12,000 feet, the air has thinned enough that the maximum range for most bullets is extended 38 percent as compared to sea level. Sorry, but I cannot find any test
results for the other two cartridges. As you can imagine, it is difficult and expensive to run testing of this type. Question: I have written about the
speed of sound in the past, but many readers and shooters I talk to at the range still ask about it, so let’s discuss it some more. Of course the reason to talk about this subject is that bullets move in the area of the speed of sound. A few leave the muzzle below that velocity, but even those that start their journey high above that point will decay down to that speed if they travel far enough before striking an object. Answer: I have usually stated
that the speed of sound, as it relates to small firearm ballistics, is basically and solely a function of temperature. Some people want to correct me on this. They say that density, barometric pressure, and humidity must be considered. Let’s examine this in more detail. First, why does a person interested
in firearm ballistics require knowledge of the speed of sound? While the speed of sound is about
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1,120 fps, there is a transonic range that begins at 0.75 Mach and extends to 1.20 Mach. (Mach 1.0 being the speed of sound, regardless of what the actual speed is.) This is the speed where the actual projectile is not at the speed of sound but if below it, some of the airflow will be pushed to Mach 1. If the projectile is slightly over the speed of sound, some of the airflow will be retarded and lag behind and the full supersonic effect will not take place. This range is roughly from 840 fps to 1,344 fps. The figures are approximate because the speed of sound is only a precise amount at a known temperature and the transonic speed is lacking in precise limits. (Disregarding density and other factors of small influence.) A lot of phenomena occur to a
projectile during this transonic range. Most of the difficulties are associated with shock wave induced flow and pressure changes. A boundary layer
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