vmfrantz
Member
I was looking at some trajectory tables and saw maxium point blank range. I dont know what it means and the importance of it when comparing calibers? Any help would be nice.. 
maxium point blank range
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Chuck Dye
Member
MPBR is the range at which the bullet drops x inches below line of sight after having risen no more than that same x inches above the line of sight. According to the Oehler Ballistic Explorer my .30-06’s favorite factory load, the Federal High Energy with the Nosler Partition 180 grain is dead on at 26 yards, 3" high just beyond 140 yards, dead on again at 244 yards, and 3" low at 286.2 yards. The idea is that out to 286 yards range will not produce more than a 3" elevation error. This is for a 6" vital zone.
Of course the Ballistic Explorer, and most other programs, works from a manufacturer’s muzzle velocity and ballistic coefficient, so the calculated MPBR is only a good starting point for testing your individual rifle.
Of course the Ballistic Explorer, and most other programs, works from a manufacturer’s muzzle velocity and ballistic coefficient, so the calculated MPBR is only a good starting point for testing your individual rifle.
rbernie
Contributing Member
Short version - it's the maximum range at which a rifle can be sighted to keep the bullet path within a specific radius.
When hunting, it's fairly common to be able to hit a wee bit high or low of the point of aim (POA), since the animals vital area isn't a dot in a bullseye but rather is a mass of lungs-n-heart. For deer, it's fairly well accepted that the vital area is actually an oval about 6" in height. Knowing this, I can sight in my rifle to never be more than 3" high than the center of this oval and the 'maximum point blank range' of the round will be the spot at which the round dips 3" below the center of the oval. This allows me to hold dead on the center of the deers vital area and not worry about holdover/holdunder so long as the range between me and the deer is less than the point-blank-range.
There is a freeware software program called 'PointBlank' that is used by handloaders to keep track of loads and plot out trajectories. It has a nice graphical view of the calculated trajectory of a given load, and calculates point-blank-range if desired. Even if you don't handload, it's worth finding and downloading, just to investigate the difference in zero settings and such.
When hunting, it's fairly common to be able to hit a wee bit high or low of the point of aim (POA), since the animals vital area isn't a dot in a bullseye but rather is a mass of lungs-n-heart. For deer, it's fairly well accepted that the vital area is actually an oval about 6" in height. Knowing this, I can sight in my rifle to never be more than 3" high than the center of this oval and the 'maximum point blank range' of the round will be the spot at which the round dips 3" below the center of the oval. This allows me to hold dead on the center of the deers vital area and not worry about holdover/holdunder so long as the range between me and the deer is less than the point-blank-range.
There is a freeware software program called 'PointBlank' that is used by handloaders to keep track of loads and plot out trajectories. It has a nice graphical view of the calculated trajectory of a given load, and calculates point-blank-range if desired. Even if you don't handload, it's worth finding and downloading, just to investigate the difference in zero settings and such.
sumpnz
Member
MPBR is mostly used in hunting. Basically it's the range within which the round will not stray vertically more than a certain distance from line of sight. Usually this is +-3".
For most hunting purposes you want to be able to put your bullet inside a 6" diameter circle out to whatever your intended maximum range might be. If you want to simply aim for the spot just above and behind the front shoulder of the deer, and not worry about holdover, you need to know what the MBPR of your rifle and load happens to be, and then stalk at least that close.
To determine your rifles MPBR you will need to establish it's ballistics. There are computer programs out there that will calculate it for you, and they often do a pretty good job. Some can also how high you need set your rifle at 100 yards (typical sight in distance) so that the max rise is no more than 3" above the line of sight, and then it will also tell you the range at which it falls to 3" below line of sight. Maximum rise will usually occur a bit past 100 yards, and the bullet will usually not fall below 3" under until around 275-300 yards for most high power rifles.
For most hunting purposes you want to be able to put your bullet inside a 6" diameter circle out to whatever your intended maximum range might be. If you want to simply aim for the spot just above and behind the front shoulder of the deer, and not worry about holdover, you need to know what the MBPR of your rifle and load happens to be, and then stalk at least that close.
To determine your rifles MPBR you will need to establish it's ballistics. There are computer programs out there that will calculate it for you, and they often do a pretty good job. Some can also how high you need set your rifle at 100 yards (typical sight in distance) so that the max rise is no more than 3" above the line of sight, and then it will also tell you the range at which it falls to 3" below line of sight. Maximum rise will usually occur a bit past 100 yards, and the bullet will usually not fall below 3" under until around 275-300 yards for most high power rifles.
litman252
Member
3 good answers
vmfrantz
Member
so would it be better to sight a rifle in at its maxium rise instead of 100 yards like most people do? For hunting deer sized animals?
All the information so far is very informitive. Thanks to all who answerd so far
All the information so far is very informitive. Thanks to all who answerd so far
rbernie
Contributing Member
Here's a reduced load that I use for hunting small deer in my 1895 Mauser:
~~~~~~~~~
Name: .284 Cal, Barnes TSX, 120 grn
Ballistic Coeff: 0.411
Bullet Weight: 120
Velocity: 2825
Target Distance: 238
Scope Height: 1.500
Temperature: 70
Altitude: 500
Ballistic Data
~~~~~~~~~~~~~~~
Range Elevation Velocity Energy ETA Drop Max Y 10mph Wind Deflect
0 yds -1.50 in 2825 fps 2126 fpe 0.000 sec 0.00 in -1.50 in -0.00 in
25 yds -0.01 in 2771 fps 2045 fpe 0.027 sec 0.14 in -0.56 in 0.06 in
50 yds 1.20 in 2717 fps 1967 fpe 0.054 sec 0.56 in -0.46 in 0.22 in
75 yds 2.11 in 2664 fps 1891 fpe 0.082 sec 1.28 in -0.27 in 0.46 in
100 yds 2.71 in 2612 fps 1817 fpe 0.111 sec 2.31 in -0.00 in 0.80 in
125 yds 3.00 in 2560 fps 1746 fpe 0.140 sec 3.65 in 0.35 in 1.22 in
150 yds 2.97 in 2509 fps 1677 fpe 0.169 sec 5.31 in 0.79 in 1.73 in
175 yds 2.58 in 2458 fps 1610 fpe 0.199 sec 7.32 in 1.33 in 2.37 in
200 yds 1.85 in 2408 fps 1545 fpe 0.230 sec 9.68 in 1.97 in 3.09 in
225 yds 0.74 in 2359 fps 1482 fpe 0.261 sec 12.43 in 2.72 in 3.95 in
250 yds -0.78 in 2310 fps 1421 fpe 0.294 sec 15.57 in 3.59 in 4.95 in
275 yds -2.71 in 2261 fps 1363 fpe 0.327 sec 19.14 in 4.58 in 6.08 in
300 yds -5.08 in 2214 fps 1306 fpe 0.360 sec 23.13 in 5.71 in 7.33 in
325 yds -7.89 in 2167 fps 1251 fpe 0.395 sec 27.57 in 6.97 in 8.71 in
350 yds -11.15 in 2120 fps 1197 fpe 0.430 sec 32.46 in 8.37 in 10.21
What you can see is that the bullet never strays above 3" high or low until just past 275 yards. In fact, the PBR of this load is 279 yards. If you look at the numbers you'll note that the rifle is actually 'zeroed' at 238 yards. That's the actual distance at which the bullet crosses the original line of sight on the downward side of the arc. Since it's not practical in many cases to zero to an odd distance, it's pretty common to calculate the rise at 100 yards and sight in on that. Therefore, to achieve a PBR zero for this load, I must zero the rifle to be 2.71" high at 100 yards.
Does this make sense?
~~~~~~~~~
Name: .284 Cal, Barnes TSX, 120 grn
Ballistic Coeff: 0.411
Bullet Weight: 120
Velocity: 2825
Target Distance: 238
Scope Height: 1.500
Temperature: 70
Altitude: 500
Ballistic Data
~~~~~~~~~~~~~~~
Range Elevation Velocity Energy ETA Drop Max Y 10mph Wind Deflect
0 yds -1.50 in 2825 fps 2126 fpe 0.000 sec 0.00 in -1.50 in -0.00 in
25 yds -0.01 in 2771 fps 2045 fpe 0.027 sec 0.14 in -0.56 in 0.06 in
50 yds 1.20 in 2717 fps 1967 fpe 0.054 sec 0.56 in -0.46 in 0.22 in
75 yds 2.11 in 2664 fps 1891 fpe 0.082 sec 1.28 in -0.27 in 0.46 in
100 yds 2.71 in 2612 fps 1817 fpe 0.111 sec 2.31 in -0.00 in 0.80 in
125 yds 3.00 in 2560 fps 1746 fpe 0.140 sec 3.65 in 0.35 in 1.22 in
150 yds 2.97 in 2509 fps 1677 fpe 0.169 sec 5.31 in 0.79 in 1.73 in
175 yds 2.58 in 2458 fps 1610 fpe 0.199 sec 7.32 in 1.33 in 2.37 in
200 yds 1.85 in 2408 fps 1545 fpe 0.230 sec 9.68 in 1.97 in 3.09 in
225 yds 0.74 in 2359 fps 1482 fpe 0.261 sec 12.43 in 2.72 in 3.95 in
250 yds -0.78 in 2310 fps 1421 fpe 0.294 sec 15.57 in 3.59 in 4.95 in
275 yds -2.71 in 2261 fps 1363 fpe 0.327 sec 19.14 in 4.58 in 6.08 in
300 yds -5.08 in 2214 fps 1306 fpe 0.360 sec 23.13 in 5.71 in 7.33 in
325 yds -7.89 in 2167 fps 1251 fpe 0.395 sec 27.57 in 6.97 in 8.71 in
350 yds -11.15 in 2120 fps 1197 fpe 0.430 sec 32.46 in 8.37 in 10.21
What you can see is that the bullet never strays above 3" high or low until just past 275 yards. In fact, the PBR of this load is 279 yards. If you look at the numbers you'll note that the rifle is actually 'zeroed' at 238 yards. That's the actual distance at which the bullet crosses the original line of sight on the downward side of the arc. Since it's not practical in many cases to zero to an odd distance, it's pretty common to calculate the rise at 100 yards and sight in on that. Therefore, to achieve a PBR zero for this load, I must zero the rifle to be 2.71" high at 100 yards.
Does this make sense?
litman252
Member
I think what is best to do is to find your MPBR, record the max raise at what ever yardage. Move to 100 yards and see where your bullet hits.
After the first trip to the range you would only have to verify the impact at 100 yards.
Hope this helps.
Tony
After the first trip to the range you would only have to verify the impact at 100 yards.
Hope this helps.
Tony
Archie
Member
Just to be pedantic...
Point Blank Range is that distance your weapon can hit an intended target without changing the sight setting. The previous posters have already explained how that works.
I get so irate about reporters talking about shootings at "Point Blank Range" implying the shooter could not miss the target.
And I have no idea why the term "Maximum" is added. In this case, the word is a superfluous modifier.
Point Blank Range is that distance your weapon can hit an intended target without changing the sight setting. The previous posters have already explained how that works.
I get so irate about reporters talking about shootings at "Point Blank Range" implying the shooter could not miss the target.
And I have no idea why the term "Maximum" is added. In this case, the word is a superfluous modifier.
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