need some help with new optic

[4x4monsterbuck]

just put a vortex viper pst MRAD 6X24 FFP EBR-2C on my 6.5 Grendel. all of the groups are vertica, nothing less than 3 inchesl. I had a leupold boone and crocket on it after I built it and was getting a lot of sub MOA groups from multiple rounds, but now nothing from the same rounds. I'm new to parallax and an optic with this high of magnification. any help would be appreciated

 

[42769vette]

I would look less at parallax, and more at mounting.

 

[257ackleyhunter]

hes right you may want to make sure everything is properly tight and that the rings you have it mounted in it are the right ones for the scope. what you could do to maybe see if its moving is take a sharpie and mark lines on the scope and the rings fire it several times each time making sure the lines stay inline and together...the sharpie will come off just use some alcohol after your done and it will clean right up

 

[4x4monsterbuck]

I have tightened, tightened and retightened to the point I'm afraid I'm going to break something. I've spent literally hours cleaning with hoppes, letting it sit and cleaning some more. At 24 power still all vertical groups. moved to 10 power and groups went horizontal. removed vortex put leupold back on and grouped a bit more than MOA at 100. called vortex they asked me to use a torque wrench and verify rings are at 13-18 ft lbs. did that tonight will have to wait to shoot until tomorrow (finger crossed).

 

[257ackleyhunter]

Ah yes torque wrench is a must have for rings...what brand of rings are you using?

 

[bruce_ventura]

I hope you used 13-18 in lbs, not ft lbs!

I think that Vortex C/S is barking up the wrong tree. I predict that your scope will be going back to Vortex for repair or replacement.

13-18 in lbs is pretty light. I usually set my torque wrench to 20 in lbs for aluminum rings. 25 in lbs is recommended by some ring manufacturers. If you applied too much torque, the tube will have indents and the parallax knob could bind. Inspect the scope tube closely the next time that you remove it. Are there obvious ring marks on the scope tube? Poorly aligned rings could cause groups to open up, but I've never seen it cause a 3" group.

If the group size is still to large in the morning, I suggest that you condition the turrets. I do this by rotating each turret from one limit to the other at least 20 times each. I wear gloves to keep my hands from getting sore. In several cases, this process has eliminated tracking problems. If that works, you may still want to send the scope back.

 

[4x4monsterbuck]

uhmmm..., yes I meant in lbs. I have little faith that this is going to fix the issue and I assume I will be returning the optic for repairs/replacement.