Moving your scope within the rings...

[nick_o_demus]

So this is more of an informative thread for those who might have a similar issue, but I would like others feedback on their experiences as well.

I recently decided I wanted to put together a "budget" hunting rifle if you will. After my nephew killed several deer with a Ruger American Predator, I decided to give this rifle a try and purchased one chambered in .308 WIN. I mounted a Vortex Crossfire II 4-12x50 on her

(bigger objective than I needed but I got it on sale) ​

with high Leupold rings and headed to the range. After dialing her in I could not consistently get three shots in a tight group to save my life. There was always one that strayed, which in all honesty was probably shooter error, but I wanted more. Upon cleaning the rifle at home I notice that the scope had moved close to 1/2" within the rings, so I obviously did not torque it enough (15 inch/lbs on initial install). My thought was to immediately loosen, reposition and torque to 18 inch/lbs, which is the max that Vortex recommended, but I fought the urge simply because I wanted to see what, if any, affect in had on the POI.

Last night I took the rifle back to the range and fired one group leaving the scope in the position it had come to. Then, repositioned and torqued and shot again. You'll see from the groups below that, while minimal, the POI was affected by the change. Take a shot at 300 yards and you'd be WAY off. All shots at 100 yards from a rest, Federal American Whitetail Interlocked 150 grain .308 caliber.

1st image - original position (top group) 6 power
2nd image - repositioned 6 power
3rd image - scope adjusted (top jerked one shot) (bottom patience and controlled breathing) 6power
4th image - max 12 power to check poi at high magnification.

Anyways, I hope this might help anyone who has a similar situation and was as curious as me.

 

[lonewolf247]

Thanks for the feedback from your post! It pretty much shows what I would have expected. Anytime you move the scope, even if it's ever so slightly, within the rings, more than likely, you will see a POI change. If nothing else, the canter, from the original position, will cause a POI change.

As far as shooting on different magnifications, this was a problem of very early variable power scopes, way back in the beginning of development. They corrected the issue, long ago, and even the cheapest scopes should be past that, but you never know, unless you verify it at the range. Every now and then, I'll try on lower magnifications. Usually, I sight in on my max power, and take 90% of my shots on max power. Never an issue though.

Really nice grouping though! Great shooting rifle!