Understanding Maximum Point-Blank Range

Maximum point-blank range (MPBR) is the distance (in yards) a projectile (bullet) can travel without rising or falling more than a predetermined measurement above or below the point of aim. For most North American big game from white-tailed deer to moose, an acceptable trajectory allowance is 6"(up or down 3" from the point of aim).

• To estimate your MPBR, you need to know the velocity in feet per second (FPS) of the projectile as it leaves the barrel of your firearm. Divide the velocity by 10 to find the MPBR (in yards). The MPBR also is affected by whether your projectile is a conically shaped bullet or a round ball.
  • Large, heavy, conically shaped bullet: Assume the velocity is 1300 FPS. Dividing by 10 gives you an estimated MPBR of 130 yards. This means that if you properly sight in your muzzleloading rifle at approximately 21/2" to 3" high at 50 yards, the projectile (bullet) will not rise or fall more than 3" from the point of aim out to a distance of 130 yards.
  • Round ball: Round ball projectiles are less aerodynamic than conically shaped bullets. The result is about a 20% loss in MPBR over conically shaped bullets moving at the same velocity. For example, use the same velocity for the round ball as for the conically shaped bullet (1300 FPS). Divide by 10 to get the distance of 130 yards. Subtracting 20% of 130 (26) gives you an estimated MPBR for a round ball of 104 yards. By properly sighting in your muzzleloading rifle approximately 21/2" to 3" high at 50 yards, the projectile (round ball) will not rise or fall more than 3" from the point of aim out to a distance of 104 yards.
• Before you go hunting:
  • Use a chronograph to find the velocity of your hunting load. Then determine the MPBR for that particular load as above. If a chronograph is not available, consult ballistic charts and ammunition manufacturers to get an idea of the velocity of your load.
  • Sight in your muzzleloader so that the projectile hits approximately 21/2" to 3" high at 50 yards.
  • After the muzzleloader is sighted in, practice shooting in the various positions (standing, sitting, kneeling, or prone) that you probably will use in the field.
• When hunting:
  • Make sure you are within your calculated MPBR before you shoot at any animal. Responsible muzzleloader hunters also consider their own personal effective range (that is, how far the hunter can shoot and keep all shots in a 6" group). Your maximum firing distance when hunting should be the shorter of the two ranges.
  • Avoid shooting from too far away. The farther a projectile travels, the less impact it will have making it less likely to kill an animal. Since reloading takes extra time, you may not shoot again before the animal moves out of your MPBR and you may have to get closer for a second shot.

To understand the relationship between trajectory and MPBR, look at the graphic above and assume that you are using 6" as your trajectory allowance. In this example, the conical bullet leaves the muzzle at 11/2" below the line of sight traveling at 1300 FPS (feet per second). At 50 yards, the projectile is 3" above the line of sight. Then, at 130 yards, the projectile is 3" below the line of sight. In this situation, the conical bullet would reach the MPBR at 130 yards.

Factors Affecting Maximum Point-Blank Range

Numerous factors, including the following, can affect the maximum point-blank range.

• Type of projectile: Typically, conical bullets will have a greater point-blank range than round balls fired from muzzleloaders.
• Weather: Wind, humidity, and temperature will affect the path and distance the projectile will travel.
• Freshness of the powder charge: Fresher powder usually will increase the firearm’s range.
• Size of game being hunted: If hunting smaller game with a vital area less than 6", you will need to adjust your firearm sights to compensate for the smaller vital area.