I got board and did some math some of you might be interested in. This is calculated on a 223, 55 gr bullet ( .237 bc) at 3100 fps. and hit range is plus or minus 2 1/2 in. If zeroed at 150 yards range is 0 to 205 yards. zeroed at 200 yards range is 140 to 230 yards. With a 300 yrs zero it`s 281 to 317 yards. At 400 yards your good from 390 to 410 yards. At 500 it`s 493 to 506 and at 600 it`s 597 to 602 yards. From this I would say that past 300 yards in the field without a range finder it`s just shoot and hope, and past 400 yards even with a range finder it about shoot and hope. Th 223, from the bench at know yardages will do very good past that, but field ain`t bench.
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zeroed at X yrads what is the plus or minus hit range?
- Thread starter Catfish
- Start date
I use this.
http://www.hornady.com/ballistics-resource/ballistics-calculator.
Point blank range can be a useful tool, but the trend is to just zero at 100 and use a scope with dots or dials. It sorta makes how flat something shoots much less important.
http://www.hornady.com/ballistics-resource/ballistics-calculator.
Point blank range can be a useful tool, but the trend is to just zero at 100 and use a scope with dots or dials. It sorta makes how flat something shoots much less important.
Are you using a scope? If so figure out the MOA or mrads that separate the lines on your reticle. You can range with that pretty easily.
The MOA calculation is (size of target in inches divided by size of target in MOA) x 95.5 equals range in yards.
There are similar calcs for milliradians and also for metric ranges.
I can easily be within 25 yards out to 800 with this method. Heck I can be within a tenth of a mile (176 yards) out to 5 miles.
But I also carry a range finder, just depends how much time I have to plan the shot.
The MOA calculation is (size of target in inches divided by size of target in MOA) x 95.5 equals range in yards.
There are similar calcs for milliradians and also for metric ranges.
I can easily be within 25 yards out to 800 with this method. Heck I can be within a tenth of a mile (176 yards) out to 5 miles.
But I also carry a range finder, just depends how much time I have to plan the shot.
PBZ (point plank ) is relative to your target.
At the USAMU Sniper School of the 70s there were a lot of Civilian Law Enforcement Agencies attending, including the SS, FBI and state and local Departments attending.
In LE there is seldom the need to engage targets beyond 300 yards (almost never), most were under a hundred. But they had to be ready to instantly engage targets further or closer in an instant.
LE Snipers unlike the military taught to make instant disabling shots (head shots), the military teaches center of mass shooting. I wont go into the whys and what for's, but that's the way it is.
The AMU came out with a Sniper/Counter Sniper guide for LE, in which they made recommendations of rifles and ammo for LE sniper use.
They recommended the 223 in a bolt gun, sighted in for 250 yards, the reason being that with that zero, the path of the bullet was never over 4 inches high or 4 inches low to 300 yards. (55 gr Ball, they didn't have many heavier bullets back the).
Thus if you could make headshots without having to make sight adjustments.
I've taught LE Snipers using this theory and it worked out quite well.
This works in hunting also, regardless of what gun/ammo combination though the zero/PBZ may be different.
You determine what game you're going to hunt. You determine the size of the vital area of that animal, and get your PBZ accordingly.
For example the vital area of an antelope averages 8.5-9 inches. Determine where to zero so the path of the bullet is no more then 4 inches low or 4 inches hide. That would be your PBZ.
On elk the average size of the vital are is 15 inches, so you can be 7 inches low or high without adjusting your sights.
All you need to know is the range to the animal. You can use range finders, MIL or MOA scopes to determine range.
Lets use mils and the two animals above. I can look through the scope of my 270 and instantly determine if the animal is within range of my PBZ. For the Antelope if it is 1.25 mils or larger, its with in range. On elk if its 2 mils or more its within range.
If beyond that, then you have to adjust or hold over. I like to adjust for longer shots as I like to shoot for hair not air.
At the USAMU Sniper School of the 70s there were a lot of Civilian Law Enforcement Agencies attending, including the SS, FBI and state and local Departments attending.
In LE there is seldom the need to engage targets beyond 300 yards (almost never), most were under a hundred. But they had to be ready to instantly engage targets further or closer in an instant.
LE Snipers unlike the military taught to make instant disabling shots (head shots), the military teaches center of mass shooting. I wont go into the whys and what for's, but that's the way it is.
The AMU came out with a Sniper/Counter Sniper guide for LE, in which they made recommendations of rifles and ammo for LE sniper use.
They recommended the 223 in a bolt gun, sighted in for 250 yards, the reason being that with that zero, the path of the bullet was never over 4 inches high or 4 inches low to 300 yards. (55 gr Ball, they didn't have many heavier bullets back the).
Thus if you could make headshots without having to make sight adjustments.
I've taught LE Snipers using this theory and it worked out quite well.
This works in hunting also, regardless of what gun/ammo combination though the zero/PBZ may be different.
You determine what game you're going to hunt. You determine the size of the vital area of that animal, and get your PBZ accordingly.
For example the vital area of an antelope averages 8.5-9 inches. Determine where to zero so the path of the bullet is no more then 4 inches low or 4 inches hide. That would be your PBZ.
On elk the average size of the vital are is 15 inches, so you can be 7 inches low or high without adjusting your sights.
All you need to know is the range to the animal. You can use range finders, MIL or MOA scopes to determine range.
Lets use mils and the two animals above. I can look through the scope of my 270 and instantly determine if the animal is within range of my PBZ. For the Antelope if it is 1.25 mils or larger, its with in range. On elk if its 2 mils or more its within range.
If beyond that, then you have to adjust or hold over. I like to adjust for longer shots as I like to shoot for hair not air.
These calculations simply tell you next to nothing useful. A 55 grain .223 starting at 3100 fps drops about 4 feet out at 500 with a 200 yard zero. PBR doesn't mean much at those distances. Not enough energy left anyway.
Ballistics calculator's are estimates at best. Far too many variables.
Ballistics calculator's are estimates at best. Far too many variables.
They are estimates at best, as are most things related. The closer you fine tune your data, the closer things will be.
For the most part, Ive found them to be pretty close, and a help when zeroing for longer distances.
Of course, you do have to verify things, but Ive found them to be pretty close if got the input right.
PBZ isnt something I would think of at 500 yards. At that distance, the vital zone would be getting silly big. Most of the ones Ive ever dealt with, PBR/BSZ, were good to around 300 yards, give or take, figuring a 8-10" vital zone.
For the most part, Ive found them to be pretty close, and a help when zeroing for longer distances.
Of course, you do have to verify things, but Ive found them to be pretty close if got the input right.
PBZ isnt something I would think of at 500 yards. At that distance, the vital zone would be getting silly big. Most of the ones Ive ever dealt with, PBR/BSZ, were good to around 300 yards, give or take, figuring a 8-10" vital zone.
There is a better way.
Its called "Mean Point Blank Range".
Here's how it works.
You figure out the target diameter. The idea is the sights are always on dead center but the bullet's path never rises above, nor falls below the radius of the target.
Now you determine the widest range of distances where this is accomplished. Frequently it will be 1/3 in front of & 2/3 behind the point where the bullet passes through the POA downrange.
That's it you shoot always with a dead on hold & stay within the min/max range where the path is within the target.
Its called "Mean Point Blank Range".
Here's how it works.
You figure out the target diameter. The idea is the sights are always on dead center but the bullet's path never rises above, nor falls below the radius of the target.
Now you determine the widest range of distances where this is accomplished. Frequently it will be 1/3 in front of & 2/3 behind the point where the bullet passes through the POA downrange.
That's it you shoot always with a dead on hold & stay within the min/max range where the path is within the target.
That is why the 50 yard zero is popular for AR-15s. With most 55 grain ammo, you will be within about two inches vertical between zero and roughly 250 yards.
You can still make shots at past that ballistic point blank range. You simply need to factor in windage and elevation. That's why the M16A2 rear sights are adjustable for both. .223rem is a fine round for medium to long range accuracy, since it is reasonably quick. The slower the bullet, the more it drops per yard of flight. That is why you need to estimate ranges more precisely at distance--the bullet is going slower and dropping more per yard traveled.
You can still make shots at past that ballistic point blank range. You simply need to factor in windage and elevation. That's why the M16A2 rear sights are adjustable for both. .223rem is a fine round for medium to long range accuracy, since it is reasonably quick. The slower the bullet, the more it drops per yard of flight. That is why you need to estimate ranges more precisely at distance--the bullet is going slower and dropping more per yard traveled.
I made this post just to give some who never thought about it an idea of why you need to verify your yardage and have an accurate drop chart when shooting at longer yardages. Point blank range is a range that you can point your gun with out having to allow for drop at and max. point blank range is the max. range at which the bullet will be within the set limits of the line of sight, no higher and no lower. The ranges I have are far bend the max point blank range and are a window in which the your specified criteria are met. As for energy left the bullet in this example would be moving at 1325 fps. at 500 yards which is the velocity of the old high velocity 22 LR HP` which have take a lot of groundhogs. Again, this is just some calculation I did for those who do not understand quite why your target gets so much harder to hit the farther out it is. I admit that I did not take all consideration of external ballistics into consideration. I did not consider wind, temp, barometric pressure or the rotation of the earth.