scope shimming

C

C7AR15

New member
Went to the range today and Savage rifle was shooting right on at 100YDS.
Cal. .308 Bushnell scope 7X-21X 3200 elite

Problem: wanted to shoot 1 1/2" high - BUT i had run out of scope adjustment.

So Just what is the amount of shim reqd? Front or Rear?? and should I click my scope adjustment to the middle of total clicks avilable ???

Thanks JD
 
I'm curious on why you don't have any adjustment. What kind of mounts/rings do you have on the gun? I've owned a lot of Bushnell Elite scopes and have never ran out of adjustment at 100 yds.
 
Before shimming

I suggest you recenter the crosshairs inside the scope. There is no scope that I know of that will "run out of adjust" in 1.5 inches at 100 yds.

The simplest (though tedious) way to center the crosshairs is:
1.run the adjustment clicks all the way up.
2.slowly and while counting the clicks move the adjustment all the way down.
3.take the number of clicks you counted and divide it by 2 and write down that number.
4.slowly and carefully count the click back toward UP until you reach the number you determined in step 3.
5. Now, complete steps 1-4 with your windage (L/R) adjustment.

Your crosshairs will now be centered inside the scope. Now, compare your point of aim with your point of impact by test firing the setup. If you have a deviation of 3-4 inches or more, NOW shim the scope in the rings to get you within an inch or less before adjusting the scope.

Now, I'm not some genius who dreamed this up. I learned from studying websites for different ring mounts and scopes. ALL the scope manufacturers say the scope is most accurate when the crosshairs are as close to the center of the scope as possible. Most scopes have 9-14 inches of adjustment (at 100 yds) when starting with the crosshairs centered in the scope where they are set before leaving the factory.

Have fun and good shooting to you.
 
Hello, cowboy..Have you checked the bases..could they be mounted opposite?..In other words..is scope pointing downward?
 
Scope

Sounds like the bases on your rifle are wrong . First are they the same height?? If not put the tallest in the rear or closest to your face when holding you rifle. From the way you describe the problem you scope is already pointing way up so you need to bring it down so either your bases are wrong or you have a problem with your scope.
 
If you have the correct bases, the easiest fix is to use Burris Signature rings with the offset insert kit. The inserts will let you align the scope to your barrel.
 
thanks

Thanks for the info everybody.

I have weaver mounts 1" - a small "block" on the receiver in the front and one small "block" in the back.

The rings that hold my scope are the type that interlock and then wrap over the scope with 2 screws holding the scope tight.
This scope and ring assembly then attaches to the base mounts.

I will drop into the gun store tommorow and bring the whole rig in and spend the money to get the proper size and good quality rings


PS My scope ran out of adjustment by being completely elevated to the top of the elevation "UP" position. The gun shot fine. But now I could not raise the point of impact even 1 click!!
 
Something is quite wrong with your setup and you need to find the source of the problem....and not try to kludge a fix together with shims or a 20 MOA base. Using either one of those just to get a scope to shoot 1.5" high at 100 yds is nothing short of silly.

What base and rings are you using now?
 
If it were mine, I would go to Bass-Pro, buy a Wheeler scope mounting kit, Maybe a new set of bases and rings,(leupold usually), and start over. Take the scope off, recenter the reticle, remount the bases, remount the rings, align the rings and torque them down, maybe lapping at this point, then remount scope, adjust relief and make dang sure the scope is level, then rezero....;) If this fails to cure the propblem then you might consider another scope of your chosing of course!:)
 
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Some quick research shows some Savage rifles have round/round mounts and others have flat/round mounts. If someone sold you Savage rings, they may be for a different model Savage than you have.

Picture of the problem?
 
ALL the scope manufacturers say the scope is most accurate when the crosshairs are as close to the center of the scope as possible.
Click to expand...

Assuming you mean as close to the center of adjustment as possible, please provide your source/reasoning for this. I have never heard that argument before.

Dozens of manufacturers- including those manufacturing high-end optics like USO- offer down-angle bases, contradicting that reasoning.
 
Oh Contrare tobnpr

Any scopes light gathering ability is best when the relicle is in the center of its adjustment range ! This is what 20 MOA bases actually do !
 
yes the +20 bases are for putting the cross hairs closer to the center for longer range shooting when you have your turrets ran way up :D
 
Checked "things"

There are so many variable when it comes to scope mounting,

1. is the top of the receiver parrell to the bore?
2. are the scope mounts machined square/true and to the right dimensions ??
3. are the rings machined concentric to the bore and the scope body ??
4. Are the scope mount hoes drilled right?
** There are MANY variables

I checked out my weaver rings and mounts and every thing seems OK

The suggestion to get Burris Signature rings with the offset insert kit is a good one. I'm going to get these rings.

[I]I recommend to everyone to watch the video on the Burris site, it is an exellent overview of scope mounting and how the signature series Rings take care of alignment issues.[/I]

Thanks for your input JD
 
JD I would recommend before purchasing any new rings I would have someone check gun/mounts.

Some 18 months ago purchased a Savage 12 223 had same problem as you, I shimmed, purchased new mounts, new rings, tried a second scope,in the end I returned gun to savage it was shipped back to me in 8 weeks with a new barrel with very little explanation. I mounted same rings/scope was on target 3 rounds with normal amount of adjustment remaining.

The Burris zee signature rings are great I use them on all my rifles however scope should properly align without shimming....

I heard some receivers left the savage factory twisted from the heat process and or incorrect boring of mount holes. Certainly don't know the facts but I had problems with mine, however have no complaints as the gun now is excellent, .600 or less consistent groups @100 yards....

My point if in doubt don't waste cash send it back to have it checked.
 
Any scopes light gathering ability is best when the relicle is in the center of its adjustment range ! This is what 20 MOA bases actually do !
Click to expand...

Not if you're shooting at 100 yards, they're not...
Take a scope with 70 MOA of total adjustment. A 20 MOA base will put a user at the very low end of adjustment at 100 yards, and leave most of it for raising POI as it's designed to do at long range.

Now, you're going to say- well, you shouldn't use a 20 MOA rail on a rifle that's going to be shot at 100 yards...and I'm still going to say "show me" where a manufacturer says this...I have never seen any information that indicated any disadvantage of a reticle being used at either the high, or low, end of it's range of adjustment.

Please explain to me how light gathering ability- which I thought was determined by tube and objective sizes- is affected by the position of the reticle.
 
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its not the only thing that having the turrets maxed out does is puts a lot of undo stress on the springs that hold the reticle
 
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