Shooting to the right

[Bucksdeermanager]

I've noticed that my setup seems to shoot slightly to the right at 200m or if using faster ammunition at 100m. For example, with 150gr bullets (in my 308) I am bang on at 100m, but 1" to the right at 200m. With faster 110gr or 130gr bullets I am 1.5" to the right at 100m. Can anyone explain what is going on?

 

[User00026]

Yes, law of deviation.

 

[Bucksdeermanager]

Yes, law of deviation.

Thank you for that incredibly astute observation. What I was asking was why the deviation is there.

 

[Alantoo]

I've noticed that my setup seems to shoot slightly to the right at 200m or if using faster ammunition at 100m. For example, with 150gr bullets (in my 308) I am bang on at 100m, but 1" to the right at 200m. With faster 110gr or 130gr bullets I am 1.5" to the right at 100m. Can anyone explain what is going on?

Shooting slightly right relative to what?

You are re zeroing every time you change your ammunition aren't you?

What size groups are you achieving?

If you do a group of 3 or preferably 5 rounds and take the average POI that is what you should use for setting the scope up.

How many rounds were involved @100 and 200yards to establish the average POI with your 150gr example?

An average POI 1" to the right at 200yards is 1/2 MOA so only one click left with a 1cm@100 click scope .

Alan

 

[Swedish]

Is your scope level?

 

[NP435]

Wind, shooter error, I doubt but do not discount spin drift even though from my very limited knowledge that's a very long range issue and 200 yds isn't long range.

 

[Rory]

I wonder if there might be a parallax error at play? Head positioning, sight picture etc might be at play. Could be worth really taking notice of scope shadow and seeing if there is any bias.

 

[Friendly Boar]

If the scope isn’t level (cant) you’ll notice the error more with distances though 200m isn’t a long distance ?

 

[Bucksdeermanager]

Shooting slightly right relative to what?

You are re zeroing every time you change your ammunition aren't you?

What size groups are you achieving?

If you do a group of 3 or preferably 5 rounds and take the average POI that is what you should use for setting the scope up.

How many rounds were involved @100 and 200yards to establish the average POI with your 150gr example?

An average POI 1" to the right at 200yards is 1/2 MOA so only one click left with a 1cm@100 click scope .

Alan

Shooting slightly right in relation to the centre of the target.

With both sets of ammunition I’m achieving 0.5 MOA groups with five shots.

Each time im testing the results with 5 shot groups. With the 150gr ammo it is bang on at 100m, but 1” to the right at 200m. With the 110gr ammo it is a similar situation.

 

[Bucksdeermanager]

Is your scope level?

I believe so - I used a Wheeler bubble level kit to set it up when I first attached it. I also didn’t think a canted scope would make any difference at that short distance?

 

[Bucksdeermanager]

I wonder if there might be a parallax error at play? Head positioning, sight picture etc might be at play. Could be worth really taking notice of scope shadow and seeing if there is any bias.

The scope has fixed parallax at 100m. Even if there was a parallax error I wouldn’t have expected it to have this much impact at 100 and 200m?

 

[User00026]

If you zero with 150g and then stick 110/130g in, they will hit to the side due to spin differential, and likely low. This will be exasperated at 200yds.

the 150g if zeroed at 100 will never hit right at 200 unless shooter error, or mechanical error (burned out barrel, scope cant, aso)

or, do you only test at 200 after 100 so the barrel is burning hot for example . Do you hold the forend or let it bounce around on a bipod?

 

[User00026]

Has a friend tested it? Could be just your style or trigger pull is off. I say that because my father and I can shoot tiny groups with either my or his rifle, but he will always group 1” right of me with the same rifle

 

[Ttocs]

Have you checked it at 20 yards? If there’s a misalignment between barrel and scope it’ll only be in plane at the zero range ie, in your case, to the left at close range then to the right beyond the zero range. However, if there is a misalignment, at short range the affect will be less pronounced than at distance but you would probably still find bullets impact to the left of a vertical line drawn through the centre of the poi.
I see a similar but exaggerated affect with my IR torch that’s mounted on the side of my NV scope. As it’s off to the side, it points slightly toward the scope so that the beam crosses the central plane of the scope at 100 yards. At closer and longer distances the beam is displaced to either the left or right.
N

 

[Bucksdeermanager]

Have you checked it at 20 yards? If there’s a misalignment between barrel and scope it’ll only be in plane at the zero range ie, in your case, to the left at close range then to the right beyond the zero range. However, if there is a misalignment, at short range the affect will be less pronounced than at distance but you would probably still find bullets impact to the left of a vertical line drawn through the centre of the poi.
I see a similar but exaggerated affect with my IR torch that’s mounted on the side of my NV scope. As it’s off to the side, it points slightly toward the scope so that the beam crosses the central plane of the scope at 100 yards. At closer and longer distances the beam is displaced to either the left or right.
N

Good suggestion. Will give it a try!

 

[RCS Deer Management]

Wind, shooter error, I doubt but do not discount spin drift even though from my very limited knowledge that's a very long range issue and 200 yds isn't long range.

Definitely not spin drift

 

[Bavarianbrit]

This might help.

 

[paul o']

Take 5 shots at 25 yrs dont move anything then re zero as needed , if same again ,take the scope set up off re set it ,do the same again rezero it shoot again if same , Barrel setup to action offset would be my 2p worth if so get windage rings sorted . is it a Rem? .

 

[Tony Morgan]

This will be exasperated at 200yds.

The error will be exacerbated, it's you who will be exasperated!