5 Degrees of Doom — The Real Risk of Unintended Down-Range Effects from Slightly Elevated Muzzles

July 18, 2022. In our Shooters Forum, we had a discussion about a range threatened with closure due to rifle over-shoots hitting a farm building more than two miles from the firing lines. One reader was skeptical and asked “How is that possible? Were these guys aiming for the stars?” You may be surprised. A rifle doesn’t need to be angled up for a bullet to land at a distance of miles. It is important that hunters and target shooters aim their barrels in a safe orientation. A small tilt of the barrel (above horizontally) can change a bullet’s trajectory. Ten Degrees? Twenty Degrees? The answer is actually much less. A typical hunting cartridge requires five to seven degrees of elevation on the rifle to create a trajectory that will allow your bullet to impact at 3000 yards. That’s 1.7 miles! Take a look at the diagram. The angle displayed for the up-tilted rifle actually is 5.07 degrees (above horizontal). We calculated 5.07 using JBM Ballistics. The angle that would produce a 3000-yard impact using a 185gr.30-caliber bullet fired at 2850 fps.MV. This would be a moderate “bookload” for a.300 WinMag deer rifle. Litz-derived BCs were used to calculate the angle drop at 3000 metres for a 185gr Berger Hunting VLD. This was at 2850 feet per second. This was calculated using the G7 BC and the JBM Ballistics Program. 60 MOA are required for every 1 degree Angle. Thus, 304.1 MOA equals 5.068 degrees. This means that if your muzzle is tilted slightly more than five degrees, your 185gr bullet (2850 FPS MV) will impact 3000 feet down-range.
The principle remains the same, even though the bullet travels slower or you shoot a bullet that has a lower BC. However, the angle required for a 3000-yard hit goes up. Let’s assume you have a HPBT MatchKing 168gr launched at 2750fps MV from an.308 Winchester. This is a typical tactical load. The total drop at 100 yards is 440.1 MOA or 7.335 degrees. This is a greater up-tilt than the example above, but it’s still not too much when you consider how a rifle might have been handled during a negligent firing. He could touch the trigger with a muzzle angle of 10 degrees or more if he is not careful. Even shooting from the bench, a rifle could be discharged before the gun is leveled. This could result in the bullet traveling over the berm and landing where it should. No one wants to cause injury or put holes in the homes of distant neighbors. Let’s return to the original example of a bullet weighing 185gr and traveling at 2850 fps. JBM says that the projectile will still travel 687 fps at 3000 meters, with 193.7 ft/lbs retained energy at that distance. This is more than enough energy for it to be deadly.