Explain this to me.

[pistolpete]

I have a 22 rifle shooting contest tomorrow so today I went out and sighted my 10/22 carbine (cheap model) in. I put a 3x9 bushnell on it. Now I zeroed it in at 75 yds set a 9 power. At 100 yds I have to aim 3.5-4 inches high. at 50 It's practically dead on, I am just a little low. AT 25 yds I turn power down to 6 and it's still dead on. At 10 yds I turn it down to 4 to get a good focus. I have to aim 1.5 inches high to hit target at 10 yds. I assume the anomonlly when shooting close up is because I am turning down the power of the scope and the 4 and 6 setting do not have the same line of sight as the 9. Because there is no way the bullet sinks and rises. :?:

 

[9x19]

Nope... it's the normal arc of a .22 Long Rifle... sight in at 25 yards, and you'll be only slightly high at 50 and dead on again at 75... low of course at 100 and between the muzzle and 25yds.

Here's a better explanation:

http://www.gunsmoke.com/guns/1022/22ballistics.html

 

[redsouthpaw]

The scope on your rifle is probably 1.5 inches above the bore. At close ranges you will need to aim a tad high to make up for this.
Look at the chart above, The 0.0 line is your scope and the 1.5 line is the rifle's bore. Gravity acts on the bullet from the moment it leaves the barrel. If the scope is dead horizontal then the barrel will be slightly canted up, the degree depends on the distance you zero.
In the example above, if you zero at 20 yards you will be 0.5 high at 40 and dead on again at 60.

 

[AzRebel]

Yep, what the guys above said.

And if you think that's odd, try mounting the scope even higher, like on an AR with a handle. It gets REALLY funky as your scope gets higher.

I always mount my scopes as close to the rifle as I can for just that reason.

Daryl

 

[pistolpete]

Wow, great explanation of why close up I have to aim high to hit target. I have medium height rings on it so it probably is 1 1/2" difference between scope and bore. I feel kind of dumb that I didn't figure that out on my own. Thanks gentlemen.

 

[Snake45]

If your scope doesn't have adjustable objective, it's entirely possible to see 1 1/2" of parallax at 10 yards.