The Maximum Point Blank Range Method is designed to simplify aiming when you may be under a lot of stress.
Imagine the largest buck or a monster bull elk you ever saw in the cross hairs at 350 yards.
It’s a reasonable shot to take in light winds, but your rifle is sighted in at 200 yards. It has already been five seconds and the animal has started to move.
Do you have time to adjust your scope?
How many clicks? Up or down?
Do you remember how many inches to hold over?
For the situation above and for my 7 mm Remington Magnum, the bullet would be 11.7 inches low (at 5,600 feet and 60°F). So I could hold over about 12 inches or that would be 3.1 MOA, which is 12 or 13 clicks up on my scope.
Personally, I would estimate the hold over based on the size of the animal’s body depth, but mentally processing the hold over for a given distance and then scaling that to an animal within a few seconds is challenging.
But if I had used the Maximum Point Blank Range Method (MPBR), I could take a shot at any distance up to 350 yards at any kill zone 9 inches or larger and be fairly confident of hitting the target.
What is the Maximum Point Blank Range Method?
MPBR is a method that takes into account the size of the kill zone and the distance that insures the maximum and minimum arc of a bullet will stay within the kill zone at given distances.
The best explanation I know is to imagine shooting down a tube or a pipe. If you are aiming for a 10 inch kill zone (conservative estimate for elk), your bullet has to go through a 10 inch pipe all the way from the muzzle to the target (Figure 1. – click on ballistics charts for larger versions).
The bullet rises when it leaves the muzzle until it almost touches the top of the pipe (5 inches above center-line) and then starts to drop until it almost touches the bottom of the pipe at the Maximum Range (5 inches below center-line).
Table 1 shows various kill zone sizes, the distance to zero the scope, the Maximum Shooting Distance and the Distance where the ballistic arc is at it’s highest point (top of kill zone) for my 160 grain 7 mm Rem. Mag at 5,600 feet and 60°F .
Table 1. Kill Zone and Maximum Point Blank Range Chart for 7 mm Remington Magnum
From Table 1, you can see for a 10 inch kill zone, the MPBR method would have me sight in at 310 yards. Then, I should simply aim for the center of the kill zone and be able to hit it up to a distance of 367 yards. The maximum trajectory of the bullet would be 5 inches high (the upper edge of kill zone) at 178 yards and the minimum trajectory would be 5 inches low at the maximum distance of 367 yards. You can see the data in the table also matches Figure 1.
If I assume a smaller kill zone like 6 inches (deer), I would have sighted in at 254 yards and shoot up to distances of 300 yards. The maximum trajectory of the bullet would be 3 inches high at 144 yards and the minimum trajectory would be 3 inches low at 300 yards.
If we use the MPBR method, we can shoot with a high probability of hitting withing the kill zone without accurately measuring each distance, but we do have to know when we are approaching the maximum distance, so we can’t leave the range finder at home.
How Does MPBR Work?
We all know the bullet starts to drop as soon as it leaves the barrel, so just like throwing a ball, we have to aim upwards to get the ball (or bullet) to arc towards the target. A perfect throw or shot correctly adjusts the angle and speed to allow the ball or bullet to hit the bulls-eye at the correct distance.
We can control the power we put into the ball when we throw it, but we have little control over the muzzle velocity of the bullet once the cartridge has been loaded or the powder has been put down the barrel. So in shooting, we have to calculate and predict the arc of the bullet based upon the muzzle velocity, weight and aerodynamics of the bullet.
When we zero a rifle at 100 yards (Figure 2), that means for a given cartridge (or load for muzzleloader), we have set the proper angle to hit the bulls-eye at 100 yards. To change the zero to 200 yards, we have to slightly increase the angle so the bullet is lobbed higher into the air to fall back to center-line at 200 yards. For a 300 yard zero, the angle is increased again.
Now we don’t keep track of the angle of the rifle barrel directly, but we do measure how many inches or minutes of angle (MOA), high or low, the bullets impact the target.
We can use a Ballistics Calculator to calculate the bullets trajectory. The calculator in the link above will automatically calculate MPBR. But you can calculate your own MPBR with other calculators by trying different zero points and then looking at the maximum height of the arc above zero and then finding the distance at which the arc is the same distance below the zero. Keep adjusting the zero until your bullet will stay inside the pipe.
For any given kill zone, adjust the scope zero distance until the highest arc of the bullet is half the distance of the kill zone. Then find the distance where the bullet is half the distance of the kill zone below the zero line. Don’t forget to account for the height of your scope. Notice in Figures 1 and 2. the bullet starts 1½ inches below the zero line because my scope is mounted 1½ inches above the barrel. A good ballistics calculator will easily make that adjustment.
Intelligent Use of Maximum Point Blank Range – Not Set it & Forget it
The MPBR method is a compromise between precision shooting and getting off a quick shot, so it is not perfect, but it is a method that will help put bullets in the kill zone if you understand the method and use it within specified distances.
I think many people think MPBR is “set it and forget it” system. That if you set the correct zero for your load and the desired kill zone then you don’t have to range the distances to your target as long as you are under the maximum distance.
MPBR will work very well if:
- You assume a full size kill zone, but actually shoot within 15% of the MPBR zero distance
- Use a conservative kill zone size for the animal you are hunting
As example, the actual kill zone of an elk is about a 14-15 inch circle. If we attempt to hit a 14 inch circle, we run the risk of missing high or low if the target is at the apex of the bullet arc or if the target is at the MPBR distance. So we need to be conservative on the distance or the size of the kill zone. I think a conservative kill zone for an elk is 8 – 10 inches, about the size of a paper plate target.
But what would you really do if you had time to range the distance and it was close to 170 yards or 367 yards as in Figure 1? Knowing that the bullet will be at the very upper or lower limit of the kill zone, would you hold on the “zero” line and hope for the best, or would you aim a couple of inches high or low to increase your chances of hitting within the kill zone?
How can we ignore the information if we have it, especially if we know what to do with that information? If I blindly follow the system, I should probably stick with the system, but if I know the exact distance to the target and also know where the bullet is near it’s maximum or minimum arc, I would adjust the shot up or down accordingly.
Since few of us have access to flat shooting ranges of various distances, we are not really going to set up targets at 284 or 269 yards and zero the scope. What we can do is adjust for the correct number of inches high at 100 or 200 yards. For me, that is 3.5 inches high at 200 yards for an equivalent zero of 284 yards and just under 3 inches (2 7/8ths) for an equivalent zero of 269 yards. Get those numbers from your ballistics calculator.
Ballistics Cheat Sheet or Range Card
In order to intelligently use the MPBR method, I always carry a card (cheat sheet) that shows my rifles ballistics when I hunt. I constantly look at it when I take breaks to make sure I know the distance where the ballistic arc is at maximum and the maximum point blank range. I also know what hold-over should be at distances out to 500 yards. Since I could be hunting at any altitude between 6,000 – 11,000 feet and at temperatures between -10° to 80° F, I have to calculate and print various cards because it does make a difference, especially past 250 yards. It should also be clear that different range cards and MPBR have to be calculated for each load, altitude, temperature and size of kill zone. That’s why BDC reticles aren’t as useful as they should be, but that is a different post. I also know what to expect from wind drift at different wind speeds and print that on the back of the card (also a different post).
After my rifle is sighted in to a MPBR range, I want a more realistic practice (read Realistic Target Practice to Prepare for the Hunt) to prepare for the hunting season. On public lands in the West, we have to prepare for long shots, but luckily, most shots are less than 200 yards. I was able to fill two tags in 2014. I shot a mule deer buck at 20 yards (muzzleloader) and a cow elk at 115 yards (rifle), but I practice shooting targets at a variety of different distances and angles, and from a variety of different supported and unsupported shooting positions to replicate the types of shots I am likely to get when stalking mule deer or elk on public land. A major part of realistic practice is estimating or ranging distances to the target in order to make a good shot and a clean kill when it counts.