Originally Posted by NWdan
First off many thanks to this site and it's members for so much valuable information. You've helped me select equipment and set up a rifle that is giving VERY good results (consistant sub MOA) to 1000 yards. I've been shooting my new Remington Sendero SFII .300RUM at 1000 yards and have an issue I can't explain and need some help with. The scope is an older Leupold 6.5 X 20 LRT, 30mm tube, 50mm obective, Night Force 20MOA two piece bases, Warne rings. I'm shooting 200g Accubonds at 3070fps. O.K. so here is the issue, with a dead on center of bullseye 100 yard zero, my groups are averaging 3 MOA right at 1000 yards with no wind. My required come up is 26 MOA (more than JBM calculates by 2 MOA?) and 3 MOA left windage. Today I shot a 5" 3 shot group and #4 opened the group to 10". This is my fifth time shooting this setup at 1K and same results each time - sub MOA groups always requiring left windage. I've noticed in Shawn Carlock's article "Reading the wind" that a right hand twist barrel can cause POI to be right. I'm assuming he didn't mean 30" right. Is it possible that my scope is to blame? When I initially mounted the scope I used the level kit to level the action and placed the second level on top of the elevation turret. After shooting at 1K at impacting right I rechecked the scope level on a building and noticed the reticle was canted left. I loosened up the scope and repositioned it so the reticle is level and plumb with the building. This results in the turret now being out of level with the action. At any rate both scope alignments result in POI to the right at approximately 3 MOA. Any thoughts or help on what could be causing this will be greatly appreciated.
I see two possibilities here. Gyroscopic drift will impact bullets to the right but shouldn't be over 30". But it could be possible. Some guns exhibit bad drift and othes don't show any at all.
The other possibility is canting of the rifle. The only really good way to mount a scope is to level on the lug raceways with a reticle leveling window tool. The level a target board and parallel the horizontal crosshair with the top of the board to double check.
Putting a level on the top of the turret sounds like a good idea, but they are not always parallel with the horizontal crosshair.
Check these two things and if it still has a problem then send it back to Leupold. You will have it back in under two weeks.