Question about windage change at 300 with no wind at all
- Thread starter 6.5guy
- Start date
Sorry guys I got it figured out just my dumb side came out in me when I had my fiancé help me with the plumb and the flash light she has bumped the gun pretty good while I was having her turn the scope to get the reticle lined up with a plumb and a flashlight that was my fault for not double checking the level befor I tightened everything down I went to the range an put up my Rex moa tracking target and put a level on the scope it was off pretty good thanks for all the help guys and gals
You should try a long piece of cardboard, like 8 ft tall at 300 yds. Put references on the cardboard and a fine aiming point. Scribe a vertical line from the aiming point. Use a long level to set it up downrange.
Use a good level on the rifle.
Shoot single shots as you systematically crank up the elevation and watch the impact climb.
I’m betting you have a plumb scope but your position is canted. That’s enough to throw it out.
Also, why not zero at 300 and just turn the knobs for closer and farther?
MatthewsCarbineCo
Home of the K.E.A.D.
Have you shot a square using dials to check the tracking
jelenko
Gold $$ Contributor
This.
Windage drifting out at distance? And the farther the target, the more the drift? It's the Plumber's Tall Target Test to the rescue!
Two things can cause this drifting problem -- canting your rifle (if you cant to the right you will hit to the right), or having a reticle that is not pointing at the exact center of your bore. Because of the slight errors manufacturers make in aligning actions to bores, you can "level" your scope to your rifle with expensive gadgets in your living room until you are blue in the face and still have windage drift at long range. It is caused by not having your reticle in perfect alignment with your bore axis, like this:
But, good news -- there is an easy, cheap, exact and foolproof fix for the mis-aligned reticle, and it involves using what for catchiness' sake I call the "plumber's tall target test." First, print off some "dot" targets on 8.5 x 11 copy paper which you will staple edge-to-edge onto a target backer, like pictured below. You want the scheme to be at least 3 pages high -- 4 pages is better. (You can buy specialty "tall targets" for this but the printed targets work just as well.)
The individual sheets should look similar to this (absent the bullet holes):
In application they will look like this:
At a time of little or no wind, set your target frame up at 100 yards, making sure the "dots" are exactly plumb by using a piece of twine with a weight tied at one end. (You can either staple the pages up and then shim under your frame legs to get the dots plumb, or you can plumb the dots as you staple the pages down -- the latter is probably smarter.
)
Then, if you have not yet tried to "eyeball" your reticle to your bore, loosen your scope ring screws and rotate your scope to make your vertical crosshair point at the center of your bore as best you can (you won't get it perfect but don't worry, you're going to fix it soon). Tighten the ring screws.
Next, shoot and sight in while keeping your reticle exactly parallel to the dots. (Since they are plumb, your reticle will be, too.) Adjust your windage turret until your rifle is dead-on at 100 yards, windage-wise (it does not matter if it is a bit high or low -- just get the windage perfect). Once it is spot-on, shoot the very bottom dot (bullseye) in a tall row, with a couple of shots.
Next, crank your elevation turret so as to raise your POI 25 - 30 moa (or as much as you can, if you do not have 25 moa available), then aim at the same, lowest bullseye and shoot again, once or twice while keeping your reticle exactly parallel to the known-to-be-plumb dots. Because you cranked up 25 - 30 moa, you should hit about that many inchies higher than the dot you aimed at. The idea is to have the upper impact hole(s) be exactly plumb over the lower impact hole(s).
Since keeping the reticle parallel to the plumb dots eliminates the possibility of cant, if your POI is to the left or right, you know that you don't have the crosshair pointed at the bore perfectly. To fix, loosen the ring screws and rotate your scope slightly (if you are hitting to the left, rotate the scope to the right, i.e., clockwise). Then repeat all of the above steps and see if you got it right. If not, repeat the process until your upper POI is exactly plumb to your lower POI, without changing your windage turret. It can be a bit of pain to get it perfect but once done you are good forever, and at any distance.
Now, it really isn't going to do much good to go to all this trouble unless your future LR shooting includes some way to see that your reticle is plumb to the earth. That is because even with your reticle pointed precisely at your bore, if you cant your rifle right or left while shooting at distance you will hit right or left of your POA. Usually the only practical way to avoid cant is to mount a level on your scope (or action).
I have a level on every one of my serious scopes. I'm partial to FlatLine Ops "flip-out" levels, but any will do. After I get the reticle pointed at the exact center of my bore, I then use the same, plumb dots on my target to set my level.
Voila! You can now shoot at any distance and (absent wind) not have your POI drift right or left.
Two things can cause this drifting problem -- canting your rifle (if you cant to the right you will hit to the right), or having a reticle that is not pointing at the exact center of your bore. Because of the slight errors manufacturers make in aligning actions to bores, you can "level" your scope to your rifle with expensive gadgets in your living room until you are blue in the face and still have windage drift at long range. It is caused by not having your reticle in perfect alignment with your bore axis, like this:
But, good news -- there is an easy, cheap, exact and foolproof fix for the mis-aligned reticle, and it involves using what for catchiness' sake I call the "plumber's tall target test." First, print off some "dot" targets on 8.5 x 11 copy paper which you will staple edge-to-edge onto a target backer, like pictured below. You want the scheme to be at least 3 pages high -- 4 pages is better. (You can buy specialty "tall targets" for this but the printed targets work just as well.)
The individual sheets should look similar to this (absent the bullet holes):
In application they will look like this:
At a time of little or no wind, set your target frame up at 100 yards, making sure the "dots" are exactly plumb by using a piece of twine with a weight tied at one end. (You can either staple the pages up and then shim under your frame legs to get the dots plumb, or you can plumb the dots as you staple the pages down -- the latter is probably smarter.
)Then, if you have not yet tried to "eyeball" your reticle to your bore, loosen your scope ring screws and rotate your scope to make your vertical crosshair point at the center of your bore as best you can (you won't get it perfect but don't worry, you're going to fix it soon). Tighten the ring screws.
Next, shoot and sight in while keeping your reticle exactly parallel to the dots. (Since they are plumb, your reticle will be, too.) Adjust your windage turret until your rifle is dead-on at 100 yards, windage-wise (it does not matter if it is a bit high or low -- just get the windage perfect). Once it is spot-on, shoot the very bottom dot (bullseye) in a tall row, with a couple of shots.
Next, crank your elevation turret so as to raise your POI 25 - 30 moa (or as much as you can, if you do not have 25 moa available), then aim at the same, lowest bullseye and shoot again, once or twice while keeping your reticle exactly parallel to the known-to-be-plumb dots. Because you cranked up 25 - 30 moa, you should hit about that many inchies higher than the dot you aimed at. The idea is to have the upper impact hole(s) be exactly plumb over the lower impact hole(s).
Since keeping the reticle parallel to the plumb dots eliminates the possibility of cant, if your POI is to the left or right, you know that you don't have the crosshair pointed at the bore perfectly. To fix, loosen the ring screws and rotate your scope slightly (if you are hitting to the left, rotate the scope to the right, i.e., clockwise). Then repeat all of the above steps and see if you got it right. If not, repeat the process until your upper POI is exactly plumb to your lower POI, without changing your windage turret. It can be a bit of pain to get it perfect but once done you are good forever, and at any distance.
Now, it really isn't going to do much good to go to all this trouble unless your future LR shooting includes some way to see that your reticle is plumb to the earth. That is because even with your reticle pointed precisely at your bore, if you cant your rifle right or left while shooting at distance you will hit right or left of your POA. Usually the only practical way to avoid cant is to mount a level on your scope (or action).
I have a level on every one of my serious scopes. I'm partial to FlatLine Ops "flip-out" levels, but any will do. After I get the reticle pointed at the exact center of my bore, I then use the same, plumb dots on my target to set my level.
Voila! You can now shoot at any distance and (absent wind) not have your POI drift right or left.
Last edited:
Great thread, Thanks all !!
Precession (Spin Drift)?
"Spin-drift" is mythological scape-goat used by people who do not bother to make sure their reticle is aligned perfectly with their bore.
....with wind flags!
How far right? Wind as many have estimated is our #1 guess; rifle can't could be next; what direction are you shooting (or on compass rose?). IE coreolis effect. Bullet spin too. Is it a target over pits; is the puller moving it? Trigger pull the same (I'm assuming so since you're good at 100). Scope elevation change changing windage?
OP figured out the problem in post #22 ??
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