sighting in Rifle

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wildwood477

New member
just sighted in my Ar the other day, started at 50 yds, then 100yds all shots within 1.5" today tried 200 yds and the string was in line left of the bull and about 3" total, A friend told me that I should use 9x when sighting in, I always use what is comfortable for me which is 4x. So question is just what power should a person use to sight in at 100yds with a 3x9 scope? One other thing, My trigger pull sucks on the Ar, real hard probably8 or more lbs. just guessing, It is a bushmaster M4.
 
normally a bad trigger causes a string to the right of point of aim (unless you are a left shoulder shooter).

But yes, you should zero at the max magnification for your scope. This is because not all scopes are consistently center the reticle throughout the magnification range. By zeroing at max power and then confirming when you back off you give yourself max accuracy for when you need to go back to max magnification for a long or precision shot.

Jimro
 
I have always sighted my scoped rifles in on max power. After sighting in I will shoot it on the lowest cause thats where it stays when in the woods. I have found scopes that shoot a lil diff on max magnification then on the lowest power.
 
This is because not all scopes are consistently center the reticle throughout the magnification range.
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That is not quite right. the reticle does not move when you change magnification. The eye relief changes. When you set up your scope, set it up at maximum magnificaton so you get the right eye relief
 
smoakingun,

What you say is true, but what I wrote is also true.

When you are rotating a lens if it isn't perfectly aligned the "exit cone" can shift with it. Next time you are at the range with a solid rest for your rifle, have someone adjust your scope magnification while you look through it. You may see the target do an oval pattern as the magnification is adjusted. It isn't really a big deal on a hunting rifle.

Jimro
 
Re: sighting in

Thanks to all for the input, guess it is never to old to learn. I never really gave sighting in a scope a big deal, but then again I have only used 2 or 4 power scopes on my hunting rifles, this being my first 3x9 power. Will go back and resight it in on max magnification, thanks again
 
When you are rotating a lens if it isn't perfectly aligned the "exit cone" can shift with it.
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That is interesting. I did not realize the lens rotated. I assumed it just slid in and out, like a camera lens. I checked an older weaver and not quite as old bausch and lomb and did not notice any shift while my wife rotated them, but I will check others
 
Here's the basic idea:
"Sighting-in" is all based upon having the same point of aim, every shot.
The more precise you can be with the point of aim, the more accurate your zero will be.

The more magnification you have with the scope (to a point, things like mirage can interfere), the more precise you can be with your point of aim, right?

This also requires a solid shooting platform. A rifle rest is best- but I use a bipod and rear bag with good results. Point is, you want to remove "shooter error" to the greatest extent possible.

Locking down the rifle, with a high-power scope aimed at precisely the same spot every shot, is the best way to zero a scope- and the only way to gauge the accuracy of a rifle and the load you're shooting. Again, it's all about removing the "human factor"...
 
100 yds all shots within 1.5" today tried 200 yds.....about 3" total
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From the op I see that the group size doubled at 200 yards. That is what I would have expected. The best group at 200 yards will be twice as large as the best group at 100 yards.( given that the shooter did everything perfectly at both ranges) 3 inch groups at 200 yards is not terrible. Unless you are planning on competition or showing off to your buddies that is respectable.
If you don't get better results with your scope set at 9 power try different ammo. Every rifle has its favorite load that it will shoot best. Try different weights of bullets and different manufacturers. If it still won't get tighter groups it's still fun to shoot it right:D
 
Agreed. Forgot to mention that 1.5 at 100 = 3 at 200- on a good day!

We found out a couple of months ago that 200 meters can be frustrating when it's blowing 15-20 at 3/4 value. Horizontal wind drift at 100 ain't bad- but at 200...well, we shoulda stayed home and saved our handloads...

In any case, 3" groups at 200 yards- particularly from an AR, and even more so with factory ammo, is nothing to sneeze at, IMO. I think you did well...
 
If you use a lower power to set your zero, any errors, however slight, will be magnified accordingly at the higher power settings. I always sight in at the highest power, then shoot some at different settings to make sure the scope is working properly.
 
Theoretically it shouldn't matter what zoom range the scope is on, the POI should be the same throughout the power range and on most good scopes (read high dollar scopes) it usually wont change, but with cheaper scope it happens sometimes.
 
Theoretically it shouldn't matter what zoom range the scope is on, the POI should be the same throughout the power range
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While this is true, I don't want to place the fate of my hunting trip on theory. Personally, I've been fortunate enough to never have had a scope that changes POI with power changes. But just as sure as I didn't check it, Ol' Mr. Murphy would rear his ugly head.
 
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