bore sight-in on 200 yards

[pashok23]

Hey guys i need a little help from you on sight in my scope at 200 yards.right now my scope is sight-in on 100 yards and i was wonderring,how much i have to do Clicks on the scope that will take me to 200 yards.thanks

[Bob33]

First, what do you mean by "bore sight-in"? Have you actually shot your rifle at 100 yards?

You need to know the velocity and ballistic coefficient of your bullet to estimate how much it will drop between 100 and 200 yards. You also need to know how much one click on your riflescope adjusts the point of impact.

[SemperFidelis97]

It really depends on the weapon, and load you are shooting.  My .270 wsm has the same zero from 100-200 yds.  Some factory ammo will have a chart on the side of the box that tells you how much bullet drop you will have at 100 yd intervals.  The only sure way to know is to spend some time at the range, and get to know your weapon.

[Zuus]

If you have 1/4" clicks I would go 4-6 clicks. Should be close enough to heart/lung shoot a deer at 200 yds. You better hit the range to make sure though.

[pashok23]

thanks for reply's guys.and i forgot to mention i have a .270 WIN with Nikon prostaff scope 3X9X50 with  1/4"clicks

[JLS]

If your zero is at 100 yards, adjust upwards about 8-10 clicks.  At 1/4 MOA this should put you about 2-2.5 inches high at 100 yards, which will give you an effective point blank range of 250 yards or so.  What this means is your rifle will hit point of impact within a 6" circle out to 250 yards, so you can hold dead on out to that range.  Further than that and you will need to hold higher.

Of course, you should verify this on paper at the range prior to trying it in the field.

Good luck.

[jay.sharkbait]

How high are the rings.

Depending on ring height, there may be no difference from 100-200 yerds

[Bob33]

Based on a few comments on  this thread, it appears that some do not understand the path of a bullet fired from a scoped rifle.

Bullets are affected by gravity and pulled downward at 32 feet per second per second from the moment they leave the muzzle of the gun.

The bullet starts below the line of sight. How far below depends on sight height. Most scopes are about 1.5" above the bore. That means the bullet starts 1.5" below where the crosshairs are pointing.

The barrel is angled slightly upward relative to the line of sight, and therefore the bullet is rising relative to where the sights are pointed. With a gun sighted in 2" high at 100 yards, the bullet first passes through the line of sight at around 30 yards. It continues in a relatively upward path, and at 100 yards is 2" high. It continues rising until it reaches its mid-point trajectory. With a 2" high 100 yard impact, a modern centerfire bullet reaches this mid-point height at around 125 to 150 yards. It then begins a relatively downward path, getting closer and closer to the line of sight. It crosses the line of sight at somewhere around 200 to 300 yards, depending on the bullet's velocity and ballistic eoefficient. It then continues to drop relative to the line of sight, getting further and further below where the crosshairs are pointed.

The only way to have a gun be zeroed (hit the point of aim) at both 100 and 200 yards is to have the scope about 5" above the bore. That's not practical.

The scope should be around 1 1/2 inches above the bore. For big game it's usually best to have a modern centerfire shoot a couple inches high at 100 yards. With a 270 firing a 130 grain bullet at around 3100 feet per second, and sighted in 2" high at 100 yards the bullet will have a mid-point trajectory of around 130 yards where it is 2 1/4 inches higher than the line-of-sight. It will be zeroed at around 235 yards. It will be 2" lower than the line of sight at around 260 yards. That makes 260 yards the "Maximum Point Blank Range" and means you can place your crosshairs on the animal from 0 to 260 yards, and the bullet will be within 2 1/4" of where you are aiming, plus or minus shooting error.

The most important thing is to practice shooting, and understand your limitations. Shooting from a bench is a good way to select ammuntion and understand the inherent limitations of your equipment, but is no substitute for field shooting experience. Unless you hunt deer from a bench rest, you must practice shooting offhand, prone, kneeling, and other positions you will use while hunting.

My rule of thumb is 90%: 9 times out of ten my first shot will place the bullet in the vitals of the animal. You can use an 8" paper plate as a good target. The distance at which you can hit the plate 9 times out of 10 shooting offhand is your maximum offhand distance. The same goes for the other positions.

Here's a good article on external ballstics to learn more: http://www.rifleshootermag.com/2010/11/02/shooting_tips_ballistics_0303/

[jay.sharkbait]

Based on a few comments on  this thread, it appears that some do not understand the path of a bullet fired from a scoped rifle.

Bullets are affected by gravity and pulled downward at 32 feet per second per second from the moment they leave the muzzle of the gun.

The bullet starts below the line of sight. How far below depends on sight height. Most scopes are about 1.5" above the bore. That means the bullet starts 1.5" below where the crosshairs are pointing.

The barrel is angled slightly upward relative to the line of sight, and therefore the bullet is rising relative to where the sights are pointed. With a gun sighted in 2" high at 100 yards, the bullet first passes through the line of sight at around 30 yards. It continues in a relatively upward path, and at 100 yards is 2" high. It continues rising until it reaches its mid-point trajectory. With a 2" high 100 yard impact, a modern centerfire bullet reaches this mid-point height at around 125 to 150 yards. It then begins a relatively downward path, getting closer and closer to the line of sight. It crosses the line of sight at somewhere around 200 to 300 yards, depending on the bullet's velocity and ballistic eoefficient. It then continues to drop relative to the line of sight, getting further and further below where the crosshairs are pointed.

The only way to have a gun be zeroed (hit the point of aim) at both 100 and 200 yards is to have the scope about 5" above the bore. That's not practical.

The scope should be around 1 1/2 inches above the bore. For big game it's usually best to have a modern centerfire shoot a couple inches high at 100 yards. With a 270 firing a 130 grain bullet at around 3100 feet per second, and sighted in 2" high at 100 yards the bullet will have a mid-point trajectory of around 130 yards where it is 2 1/4 inches higher than the line-of-sight. It will be zeroed at around 235 yards. It will be 2" lower than the line of sight at around 260 yards. That makes 260 yards the "Maximum Point Blank Range" and means you can place your crosshairs on the animal from 0 to 260 yards, and the bullet will be within 2 1/4" of where you are aiming, plus or minus shooting error.

The most important thing is to practice shooting, and understand your limitations. Shooting from a bench is a good way to select ammuntion and understand the inherent limitations of your equipment, but is no substitute for field shooting experience. Unless you hunt deer from a bench rest, you must practice shooting offhand, prone, kneeling, and other positions you will use while hunting.

My rule of thumb is 90%: 9 times out of ten my first shot will place the bullet in the vitals of the animal. You can use an 8" paper plate as a good target. The distance at which you can hit the plate 9 times out of 10 shooting offhand is your maximum offhand distance. The same goes for the other positions.

Here's a good article on external ballstics to learn more: http://www.rifleshootermag.com/2010/11/02/shooting_tips_ballistics_0303/

"Bullets are affected by gravity and pulled downward at 32 feet per second per second from the moment they leave the muzzle of the gun."

Wrong.........The bullet is accelerating downward at 32 FPS. It takes one full second for the bullet to reach that 32 FPS number.

[Bob33]

"Bullets are affected by gravity and pulled downward at 32 feet per second per second from the moment they leave the muzzle of the gun."

Wrong.........The bullet is accelerating downward at 32 FPS. It takes one full second for the bullet to reach that 32 FPS number.

Downward acceleration of 32 feet per second per second starts the moment the bullet leaves the barrel. The statement did not indicate the bullet was travelling 32 feet per second when the bullet left the muzzle. In fact, the bullet is not travelling downward at 32 feet per second after one second unless the shot is horizontal to the surface of the earth.

[norsepeak]

Based on a few comments on  this thread, it appears that some do not understand the path of a bullet fired from a scoped rifle.

lol, was thinking the same thing.  I run into this "dilema" all the time with clients who are shooting "experts", makes me laugh.

[kbrowne14]

32 feet per second per second is a pulliing force of gravity.  Therefore no matter what angle you shoot a bullet, gravity pulls at a consistent rate of 32 fpsps.  Gravity is pulling the bullet down as it sits in your magazine.  It will pull your bullet down accelerating 32 feet per second every second, there are factors such as inertia, wind resistance, and others that will affect that acceleration.  But in a world without air, everything would fall the exact same.  A piano would fall at the same rate as a feather.  You can test this, put a feather on the back of a book, drop the book, the feather will fall with the book because there is little air resistance.

[Blacktail Sniper]

Physics makes my head hurt.  How about he just go to a range/area with a 200 yard target and shoot?

[pashok23]

Got it all done.out of 3 shots after adjusting with 4 clicks up,it took me to 200 yards.it was close to bulls eye, even tho i was shooting from 182 yards thats the best i could find around my area to shoot.but still its only 18 yards diff from 200.it shouldnt be an issue.right?

[Bob33]

Got it all done.out of 3 shots after adjusting with 4 clicks up,it took me to 200 yards.it was close to bulls eye, even tho i was shooting from 182 yards thats the best i could find around my area to shoot.but still its only 18 yards diff from 200.it shouldnt be an issue.right?

You should be fine; 18 yards is insignificant. Now go practice, and then find a critter to shoot.

[pashok23]

Thanks Bob 

[LEN]

Thought I was remembering my physics. This is right from the book on a falling object. Point being you start at 0 and at 1 sec you dropping at 32 fps so the first second you drop 16 feet.
This o fcourse this assumes your wife isn't the one who pushed you over the edge.

 Time interval   Avg. speed   Dist moved   Cumulative distance
  -------------   ----------   ----------   -------------------
  0 to 1 second    16 ft/sec      16 feet       16 feet
  1 to 2 seconds   48 ft/sec      48 feet       64 feet
  2 to 3 seconds   80 ft/sec      80 feet      144 feet
  3 to 4 seconds  112 ft/sec     112 feet      256 feet


OH and just for the record all my big game rifles are sighted at 200 yards.

LEN

[ICEMAN]

Based on a few comments on  this thread, it appears that some do not understand the path of a bullet fired from a scoped rifle.

Bullets are affected by gravity and pulled downward at 32 feet per second per second from the moment they leave the muzzle of the gun.

The bullet starts below the line of sight. How far below depends on sight height. Most scopes are about 1.5" above the bore. That means the bullet starts 1.5" below where the crosshairs are pointing.

The barrel is angled slightly upward relative to the line of sight, and therefore the bullet is rising relative to where the sights are pointed. With a gun sighted in 2" high at 100 yards, the bullet first passes through the line of sight at around 30 yards. It continues in a relatively upward path, and at 100 yards is 2" high. It continues rising until it reaches its mid-point trajectory. With a 2" high 100 yard impact, a modern centerfire bullet reaches this mid-point height at around 125 to 150 yards. It then begins a relatively downward path, getting closer and closer to the line of sight. It crosses the line of sight at somewhere around 200 to 300 yards, depending on the bullet's velocity and ballistic eoefficient. It then continues to drop relative to the line of sight, getting further and further below where the crosshairs are pointed.

The only way to have a gun be zeroed (hit the point of aim) at both 100 and 200 yards is to have the scope about 5" above the bore. That's not practical.

The scope should be around 1 1/2 inches above the bore. For big game it's usually best to have a modern centerfire shoot a couple inches high at 100 yards. With a 270 firing a 130 grain bullet at around 3100 feet per second, and sighted in 2" high at 100 yards the bullet will have a mid-point trajectory of around 130 yards where it is 2 1/4 inches higher than the line-of-sight. It will be zeroed at around 235 yards. It will be 2" lower than the line of sight at around 260 yards. That makes 260 yards the "Maximum Point Blank Range" and means you can place your crosshairs on the animal from 0 to 260 yards, and the bullet will be within 2 1/4" of where you are aiming, plus or minus shooting error.

The most important thing is to practice shooting, and understand your limitations. Shooting from a bench is a good way to select ammuntion and understand the inherent limitations of your equipment, but is no substitute for field shooting experience. Unless you hunt deer from a bench rest, you must practice shooting offhand, prone, kneeling, and other positions you will use while hunting.

My rule of thumb is 90%: 9 times out of ten my first shot will place the bullet in the vitals of the animal. You can use an 8" paper plate as a good target. The distance at which you can hit the plate 9 times out of 10 shooting offhand is your maximum offhand distance. The same goes for the other positions.

Here's a good article on external ballstics to learn more: http://www.rifleshootermag.com/2010/11/02/shooting_tips_ballistics_0303/

Bob, your write up is without a doubt the absolute best description of this topic I have ever read. Kudos!!!

You should consider copy and pasting into a sticky so it can be revisited by members all year long.

Again, thanks for taking the time for such a well worded, clear write up.