I have just put togther an anchutz 1712 with low rings and a leupold 25 power fixed scope. How much shim under the rear mount should I start with to center the scopes adjustments?

Try bore sighting it, you may not need any shim for adjustments.


Mary

I would not shim one ring and not the other unless
using Burris signature rings with rotating inserts.
This places undue torque on the scope tube and
is likely to crease or bend your scope.

With standard rings I've had to shim ever scope I've put on to use in the SB silhouette game. We're only talking about .002 to .005 inches. In my opinion not enough to do any damage. That being said I would bore sight it first than shoot it and see where to adjustments from chickens to rams fall in the range of the scope turrets adjustments. You want the turrets to be roughly in the middle of their travel and not to the extremes.
ppkny

I would use 2 thickness of a beer can metal under the back.

For a silhouette gun, it's best to use imported Mexican beer cans.

I have not had to use shims on the 25 or 30 power from Leupold. Only on the 6.5 x 20 Var.

Byron

Jerry G wrote:I would use 2 thickness of a beer can metal under the back.

I'm not sure that's NRA legal, should probably stay on the safe side and use a soda can.

Trent wrote:

Jerry G wrote:I would use 2 thickness of a beer can metal under the back.

I'm not sure that's NRA legal, should probably stay on the safe side and use a soda can.

So long as we don't catch you licking your scope rings there won't be any problems.

Lightly lapping your rings with some compound will eliminate any torque from the few thousandths of shim under your rings. I always shim at the dovetail under the ring not in the round part where the scope goes. This allows the lapping to square things up really quick.

JOE
We like to have you and the rest of our friends show up at the TEXAS STATE CHAMPIONSHIP in Houston in March.
By the way, shimming the bottom of the rear ring in the scope won't hurt anything, as a matter of fact, as stated before by others, I think that 90% of the scopes being presently used are shimmed.

Evelio,
Maybe 90% of your scopes are shimmed, but only one of the 18 rifles I had out this weekend are shimmed, and that is a on a POS Simmons scope on a cheap 64 action. About to pull it and put on a decent scope and set of mounts.
Not that there is anything wrong with shimming, but if things are set up and built properly to begin with then shimming should not be needed.
Mary

FWIW None of the silhouette rifles that Mini Kitty or I have shimmed scopes...All are in the mid range of adjustment.

Kitty

Mary
What kind of event did you go to this week end, you actually shot 18 rifles WAO.
Wether you have to shim a scope or not, it depends on several factors, first the scope of course, a lot off the older high magnification scopes were not design to adjust from 40 yds. to 600 yds. second the height and quality of the rings and bases has a lot to do with the amount of adjustment left on the scope, the higher the rings the worse it can get. Now take it for granted, some of the newer high priced scopes were design with Silhouette competition in mind, and don't require any shimming. A lot of the reasons for shimming is to stay somewhere close to the center of the adjustment, which is ideal, but not absolutly required. In some of my not shimmed scopes, I only have about 3 minutes left before I run out of elevation, but they still tract on the money. Some scopes, when you get close to max out on elevation, the windage point of impact changes quite a bit, I seen some that it actually moves as bad as 4 " at 100 meters.
One of the most critical investments when building a match rifle, is the quality of the scope. I for once am guilty of using a $2000.00 gun with a $200.00 scope. Since I started shooting benchrest, is when I finally realise how critical a good scope is, I just could not bring myself to spend $1000.00 for a good scope.
The point I am trying to make is, if a scope needs to be shimmed to reach all required distances, when done properly, it will not damage the scope.
This is an old subject, that has been discused, and talked about for many years, with all kind of opinions and sugestions, with no definite results.
Evelio.

Crazy Cuban,
I am working with several juniors locally at the club matches and loan my rifles out to them, at the matches. I have not had a chance to shoot my normal match rifles for about 5 months now as they are on loan at all the local games.
As for shimming, I agree it will not damage the scope, and in fact have done it in the past with poorly set up rifles...my point is I do not believe that 90% of the rifles at a silhouette match have shimmed scopes. So, if 90% of what you have are shimmed, then why not take the time to get the correct (whether you build or buy it) set up for the rifles?

Mary

You guys make fun of the beer can but, between the Eley powder and the Bud Light shims, I have the best smelling rifle on the line.