Can I tell if my scope is going straight up and down with a bore sighter?
It seems to be moving very slighty to the left when I adjust it all the way up then to the right when adjusting down.
1/2 a grid.?
Could it be to rough a device to check scope?
I have used my multiple caliber, arbor type, grid collimator as a supplemental devise when setting up my scopes for several years for testing the elevation tracking to make sure it's plum, and to do a box test see if the scope tracks ok. I always confirm with actual shooting tests, but will have to say that it does work quite well if you have a good collimator and you follow a set procedure. I have to say that I also had two scopes over the years that showed up defective in their tracking before I ever shot the rifle and saved myself a lot of greif. They were sent back and repaired. I was able to confirm they were fixed using the collimator. The procedure is use is:
1. Mount the scope using a bubble level to square the bolt rails and the scope.
2. With the levels still on the rifle and scope, Mount a plum line on the wall to check that the scope reticle is in fact plum. If not turn the scope so it is. This is rare with a good scope.
3. With the levels still on the rifle and scope, mount the collimator and turn it so that the vertical cross hair is exactly on the same line as a vertical gridline in the collimator. Usr windage on the scope to line it up.
4. Being very careful not to move the rifle, I run the turret elevation at least 20-25 minutes from my approximate zero setting. The crosshair should not deviate off the collimator line. I also count the clicks up and down 3 or 4 times to make sure the crosshair ends up at the same place on the collimator and it stays exactly on the line. If not, turn scope to correct.
5. I then do a box test on the collimator to check the tracking of the scope that now includes the windage adjustment. Check start and finish points. All this also serves the purpose of running in the scope and spreading the lube on the elelvators.
6. Confirm with actual shooting. I use 100 yards, group at zero, group at 20 minutes up. Double check at 500 yards with no wind.
Sounds like a lot of work(my buddies think I'm nuts), but it has worked with my last half dozen LR rigs, and I have found that the field results matches my collimator results and have not had to readjust my scope after set up.