SHIMMING A SCOPE

[JerryP]

I have to add more moa to my rifle. Does anyone know the formula for adding shims to the rear of the scope and what effect it will have at 100 yards? As anyone shimmed a NF scope?

 

[sawcarver]

Burris signature rings with the inserts are the way to go no damage to the scope tube or marks

I have used credit card shims before but it's not the ideal/professional way to do it

 

[CoyoteTan]

I haven't done it myself, but I know guys used a piece or two of beer/coke can to shim their scope.

No effect zeroing at 100 yards.

 

[6MMsteve]

use 1/2 to 3/4 inch tape measure it's 6- 8 moa per pc I think, place under the base, the radius matches the receiver, use dow rod under the tape to drill holes clamped

 

[geraldgee]

If you are going to add a shim under your base would be well served to bed it ensuring your base is properly supported where it contacts your action

Good luck.
Gerald

 

[mr45man]

2 piece base , shims under one = damaged scope tube.
Burris rings will do what you need safety.
If you need more moa with a Night Force get a base with the Moa
You need.

 

[Bart B.]

The formula:

Distance between ring centers divided by 3600 equals 1 MOA dimension.

For example: 5 inches / 3600 = .00139"

A .014" thick shim raises the back ring 10 MOA at a 5" spacing. Scope is now pointing 10 MOA lower.

 

[Nature Boy]

I used homemade shims cut from the side of a coke can until I could get a set of Burris Signature Zee rings with the corresponding inserts.

The latter is the better solution but the former will work in a pinch.

 

[Howland]

I had to shim a mount once because I ran out of vertical adjustment to sight in at 100 yards.

I used a blade from a spark plug gap guage set. I calculated how many inches I needed to come down, then how far apart the rings were like @Bart B. did above. It worked out pretty well.

 

[Dgd6mm]

I shimmed the rear of my 1 piece base with a piece of the bottom of an aluminum can. The bottom is thicker than the side. I picked up 8 MOA.

 

[243winxb]

Hope this helps. From Bushnell.

 

[drags]

Brass shim stock can be purchased from a hardware store or online .005 .010 .015 .020 ect. I shim the rear base and lap the scope rings.
Drags

 

[Bart B.]

Hope this helps.

They're off by 11%, if that matters.

 

[Bart B.]

If you prefer the trig formula instead of the one preferred by the National Shooting Sports, divide ring spacing by 3,437.7468731973 to get its MOA value.

 

[johnfred1965]

I shimmed the rear base on my Cooper. My brother and I calculated about 21MOA using his knowledge of Trig. When I sighted it in, it was exact. It however left the rings uneven. Luckily, my brother is a machinist, and he also cut the rings on an angle so they would align without stress. A little lapping and I was good to go.

 

[Bart B.]

I wonder if when selecting a shim if a recycled feeler gauge blade trimmed to size may be the ticket
J

Yes. Been there, done that.

 

[slm9s]

+1 for Burris Signature Zee rings, or if weight isn't an issue Burris Signature XTRs are even better.

But I have used cardboard/paperboard before and had no issues.

 

[tonyb]

+1 for the Signature Z Rings. The correct and easy way to do it.

Tony.

 

[JerryP]

Thanks for all of the help. Bought the Burris signature rings.

 

[tonyb]

Thanks for all of the help. Bought the Burris signature rings.

Good move.