Post by: pashok23 on September 01, 2013, 08:20:53 PM
Post by: Bob33 on September 01, 2013, 08:26:25 PM
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.
Post by: SemperFidelis97 on September 01, 2013, 08:28:50 PM
Post by: Zuus on September 01, 2013, 08:37:08 PM
Post by: pashok23 on September 01, 2013, 10:59:33 PM
Post by: JLS on September 02, 2013, 12:30:57 AM
Of course, you should verify this on paper at the range prior to trying it in the field.
Good luck.
Post by: jay.sharkbait on September 02, 2013, 07:48:23 AM
Depending on ring height, there may be no difference from 100-200 yerds
Post by: Bob33 on September 02, 2013, 08:30:10 AM
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/ (http://www.rifleshootermag.com/2010/11/02/shooting_tips_ballistics_0303/)
Post by: jay.sharkbait on September 02, 2013, 08:59:08 AM
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/ (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.
Post by: Bob33 on September 02, 2013, 09:06:28 AM
"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."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.
Wrong.........The bullet is accelerating downward at 32 FPS. It takes one full second for the bullet to reach that 32 FPS number.
Post by: norsepeak on September 02, 2013, 09:56:11 AM
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.
Post by: kbrowne14 on September 02, 2013, 11:28:54 AM
Post by: Blacktail Sniper on September 02, 2013, 11:35:38 AM
Post by: pashok23 on September 02, 2013, 01:59:11 PM
Post by: Bob33 on September 02, 2013, 02:56:12 PM
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.
Post by: pashok23 on September 02, 2013, 03:54:56 PM
Post by: LEN on September 02, 2013, 06:19:24 PM
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
Post by: ICEMAN on September 02, 2013, 06:33:48 PM
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/ (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.