Rifle Scopes Optic Failure

[mdmp5]

I tend to have very bad luck with equipment, whether we are talking about out of spec, broken, tolerance stack or straight up mishap on my part.

On Wednesday, went to the range to confirm my rifle was shooting well, because I had to shoot a 600 yd qualifier yesterday. Shot 1 group at 300 that was about .09 moa, and another one with almost zero vertical, as the wind started blowing really hard. Yesterday, I line up with the RO on the 300 yd line, and my fuckin rifle is shooting 2 mils high. Shooting a Kahles, so you cannot dial down because of the automatic zero stop. I was dumbfounded, and then I realized what was happening. I am a perfectionist with some things, and when I mount a scope, I always place the rings on the tube equidistant from the turrets. The scope was pushed forward pretty good, with the front ring hugging the turret, and the rear very close to the zoom.

I think what happened was multifactorial. I am using ARC rings and I think I only cranked them to about 20 in*lbs on the tube instead of 55 when I mounted it last year. If this is the case, I might have confounded Seekins instructions with these. Then how did it shoot so well on Wednesday and last year? I think with the gun sitting in the sun, the metal heated up and expanded just enough to make everything snug. Yesterday was cloudy, so the scope was able to move under the recoil. I took it back to the 100 yd line, disengaged the zero stop and re zeroed.

The question I have is why my elevation would change by 2 mils if the scope simply slid forward?

 

[VegasHKShooter]

Anything can cause a shift, and certainly that much movement could. I have literally seen a change of muzzle device move a zero an inch or so up and an inch or so left/right. That’s just due to the gasses changing at the muzzle. So yes, you can get significant shift from the amount of movement you’re talking about.
Reset everything, torque to 55in lbs (sorry, you already did this), and start over. If it fixes it, like I’m betting it will, drive on. If not......we investigate further. No sense getting rattled yet.

 

[mdmp5]

Oh yes I did re zero and torque. I was just a bit puzzled why the elevation would change so drastically without the ability to come back to zero by moving the scope back. It seems I got it working now.

On another note, in this experience, I noticed a floater near the reticle, and when I use the illumination, an asymmetrical ring shows up in the field of view. I think dust got kicked up from the scope being jolted. Got an RMA and I should be sending it back to Austria soon

 

[VegasHKShooter]

That sucks that you have to send it back, BUT, the updated is they will give it a once over and ensure all is well. That’s good if for nothing more than the peace of mind.

 

[magtech]

I find the harder I look for problems the more I find. Sometimes I find problems that aren't really the (an) issue, but I focus on them making them the issue. By the sounds of it you know what you're doing and will find the culprit. Good Luck.

 

[LunaCustomGuns]

Bummer. My instructor always checked rings first when a student had an issue.

 

[CSTactical]

Bummer, your not the first guy to do that with ARC rings.