SCOPE ADJUSTMENT HELP

TDAVIS

TDAVIS

New member
O.K. guys need some help. Trying to sight in a new gun yesterday and I ran out of elevation adjustment on the scope. The scope is a bushnell elite 4200 8-32x40. I have med. leupold rings. Just took the scope off of my 22-250 and didnt have any problems with it. I thought it might be stuck so I moved the crosshairs the full range of motion, still nothing. Any ideas?

TJ
 
Your local gunsmith should have steel shims for that problem, or Brownells. That problem is fairly common, and from I've seen, Winchesters seemed to be the worst offender there. Their receivers apparently aren't very consistent.

You mention running the dials through their range. If you do that with a boresighter, you can actually verify the travel of the crosshairs. Sometimes, when the spring systems fail in a scope, you will observe that when you go "right" or "up", and are relying on the springs to make the erector tube move, nothing happens. (or at the range, guys adjust the scope, then tap it a few times...) Time for an overhaul. I had 30+ yr. old Leupold do that this spring. Sent it back, and now its fine.

Thats why its never good to operate a scope at the extremes of its range. You either crush the springs, or have very little tension on them. Nightforce is the exception in my experience, as they use a much better spring system. (coil springs, w/17# tension, teflon caps, vs flat leaf springs, 4-6# tension, lots of friction...)
 
What brdeano suggested is the best way, I never liked shimming a scope as it can put some real pressure on a scope tube. The Burris Signature Pos-Align use plastic offset inserts that solve problems like this with no stress on the scope tubes.
 
I have no love for imparting any unnecessary stress by shimming anything.

I have only ran into one instance of having to resort to pos-aligns. It was on a savage and it solved the issue less any fuss.
 
Shimming does not put any stress on the scope if you lap in the rings, which should always be done unless using the self aligning rings.

Jack
 
Right on, regarding lapping. I've always said, once you lap one set of rings, and see what it does, you will tear apart every rig you own, and lap them too.

Mount a Nightforce, w/o lapping the rings, and see what happens. That scope is very rigid, and I have seen an action that wouldn't close all the way, because the scope, with misalignment of the rings, twisted the action. Now, this was caused by a fellow trying to machine his own tapered bases, but it was still pretty unbelievable. This was on a Rem. 700.
 
Does your comment about "Moving the Crosshairs the Full Range of Motion" mean that you also Centered the Crosshairs upon the completion of all that turning? Also, if you would, what type of rifle, what style of rings and mounts? and did you make your initial horizontal corrections when sighting in, using the scope adjustments or the windage screws on the mounts?
 
Where you have windage adjustable bases, like Leupold, yes, the scope should be set at center, and brought in line with the bases. Commonly, scopes have about 4 1/2 rotations on the adjustments, so ~2 1/4 is center. New scopes are normally centered out of the box.
 
try reversing the rings, (back to front, front to back), see if that changes anything. If not it could be a bent tube or your reciever out of spec (it happens I put 3 grand in a custom LR rifle and with 20 MOA bases couldn't get the POI low enough to make a 100 yrd zero, and the scope has 105 MOA of elevation adjustment, So I installed a set of "0" moa bases and the 100 yd zero is 13 MOA of the down stop. Its a rem 700 BTW)
RR
 
Sorry Mark Shubert----Onionskin may have been going here-- but actually the windage adjustment can make a difference in the amount of elevation adjustment available. There is more adjustment in the elevation axis when the windage or horizontal adjustment is in the middle of the scope. If your windage adjustment is not centered, and let's say your unknowingly over fairly tight against the right or left side of the scope, the curvature of the scope prevents the verticle adjustment from going to the top of it's potiential adjustment range. I'd never thought about this until I read about it in Leupold's Q&A website section a few years ago. They probably explain it better than I do.
 
Thanks for all the help guys I found the problem. I placed it in the vise and tested the scope with the boresighter, only to find the scope is F.U.B.A.R. the crosshairs will only move with the first 16 clicks of adjustment. the turrets still spin with a possitive click but the crosshairs are locked up. Now its time to find out how well bushnell stands behind there products and how good their customer service is.

Thanks again,
TJ
 
Back
Top