Barrel squint?

[CamTheBam]

Hi Guys,

I appreciate that when you are dealing with factory rifles, it's often rare to find that your desired zero is exactly the same as the optics 'optical centre'.

By 'optical centre' I mean, optimising the performance of the various lenses within the scope by centring them within the scope, before mounting the scope on the rifle. I use two methods to find the 'optical centre', the 'mirror' method and the 'counting clicks' method.

In terms of MOA, just how far off 'optical centre' would you consider normal/acceptable, and when does it become a problem?

On one particular rifle, I'm having to apply 10MOA+ of windage to achieve a zero at 100yds. I've repeated the test using three different quality scopes now (Vortex Razor, Swarovski X5, Nightforce NXS).

Would you consider 10MOA+ of windage correction to be excessive on a factory rifle? It shoots fine at 100yds, and it groups beautifully – but I fear that as I walk it out to longer distances, and the effect of the wind is compounded, I could run out of windage adjustment very quickly.

Many thanks.

 

[cahunter805]

Scope base holes are probably off center. What rings and bases are you using? I'd lap them and see what they look like then.
10MOA isn't terrible but if it bothers you then it can be fixed.

 

[hammerjack]

Should be able to get 10MOA with Burris Signature Zee Rings ; stand the inserts up & set them which every way you need more MOA.

 

[Dusty Stevens]

Barrel indexed wrong. Factory barrels arent known to be straight

 

[CamTheBam]

It's a Ruger Precision Rifle, with a Tier One Monolithic mount.

 

[Roeder]

Would you consider 10MOA+ of windage correction to be excessive on a factory rifle? It shoots fine at 100yds, and it groups beautifully – but I fear that as I walk it out to longer distances, and the effect of the wind is compounded, I could run out of windage adjustment very quickly.

Many thanks.

No.
10 MOA Scope misalignment is not unusual for a factory rifle. Not saying it is a good situation, just a common one.

 

[CamTheBam]

Great, thanks for all the feedback, guys!

 

[Ggmac]

Hi Guys,

I appreciate that when you are dealing with factory rifles, it's often rare to find that your desired zero is exactly the same as the optics 'optical centre'.

By 'optical centre' I mean, optimising the performance of the various lenses within the scope by centring them within the scope, before mounting the scope on the rifle. I use two methods to find the 'optical centre', the 'mirror' method and the 'counting clicks' method.

In terms of MOA, just how far off 'optical centre' would you consider normal/acceptable, and when does it become a problem?

On one particular rifle, I'm having to apply 10MOA+ of windage to achieve a zero at 100yds. I've repeated the test using three different quality scopes now (Vortex Razor, Swarovski X5, Nightforce NXS).

Would you consider 10MOA+ of windage correction to be excessive on a factory rifle? It shoots fine at 100yds, and it groups beautifully – but I fear that as I walk it out to longer distances, and the effect of the wind is compounded, I could run out of windage adjustment very quickly.

Many thanks.

I find that a v cut in a shoe box and the scope rotated while looking thru it against a white wall is more accurate as a optical center .
It'll be an elliptical till you zero it then the cross hairs center will not move .

 

[Dusty Stevens]

I put the objective lens up to a mirror in a well lit room. Way easier than v blocks. Give it a try its simple to see

 

[tobnpr]

I don't see a correlation, at all, between actual point of impact, and "theoretical" point of impact based on a straight- line extension of the centerline of the bore

I've seen enough, super-slow motion video of barrel whip (harmonics) to believe that the direction-and location- of the muzzle in space at the moment the bullet is released, varies widely based on the bullet/load and other variables. It's why we do load development....

Timing the shock wave that travels back and forth the length of the barrel many times per second is what determines the correlation of optical center to actual point of impact IMO, and it's impossible to separate this variable from muzzle indexing, bore concentricity, and other variables affecting "accuracy".

JMO....

 

[Ggmac]

Optical center is important for optical clarity and more / equally important to fully have all your adjustment for wind and elevation not correcting mechanical imperfections.

 

[Ggmac]

I put the objective lens up to a mirror in a well lit room. Way easier than v blocks. Give it a try its simple to see

I have , it is easier but when rechecked in v blocks , it's a little off . Probably like me !

 

[Dusty Stevens]

I have , it is easier but when rechecked in v blocks , it's a little off . Probably like me !

Half a bubble off? I suffer from that syndrome.