Shimming a 'scope

[ovenpaa]

I need to shim a scope to bring up the back ring by 10MOA can someone cleverer than me tell me how many thou that is please? I just worked it out as .014" which seems wrong to me.

Confused of Bedfordshire...

[Dougan]

I need to shim a scope to bring up the back ring by 10MOA can someone cleverer than me tell me how many thou that is please? I just worked it out as .014" which seems wrong to me.

Confused of Bedfordshire...

You're 'speaking in tongues' again ('shim a scope' :? ) - I'm not sure, as I've always thought of MOA to be relative to the distance your calculating...but I've just taken a measurment of the scale on my TR rear sight, and 10MOA appears to be bang on 0.1"....

[ovenpaa]

That sounds more like it

I want to get the range zero of the 'scope on the S&L as close to the mechanical zero as possible so I have the full range of elevation available, not that I need the 80MOA available it is just that I prefer to be as close the bottom stop as possible if that makes sense.

Or put it a different way, when I am zeroed at 100 I cannot go down any more clicks on the 'scope.

[Dougan]

That sounds more like it

I want to get the range zero of the 'scope on the S&L as close to the mechanical zero as possible so I have the full range of elevation available, not that I need the 80MOA available it is just that I prefer to be as close the bottom stop as possible if that makes sense.

Or put it a different way, when I am zeroed at 100 I cannot go down any more clicks on the 'scope.

Cheers - that makes sense :idea:

I've though about that at short range (GR) - I'm not sure what difference it would make at long range...but for you F class guys, a few centimeters can make a difference to the score....

[Robin128]

If you shim the ring will that not lead to bending the scope tube?...don't you mean shimming the rail???

:roll:

[ovenpaa]

The biggest thing for me is finding zero so I can wind back up again, so if I shoot at 400 and then want to go to 900 the following week I know where I am. Some people know their zero is at say 11.5MOA and work off that but I am so used a S&B 'scope that has a physical and actual zero of 100m and I much prefer it to having to either wind down to a number then count the clicks back up to a zero and then add the elevation required. Just one thing less to worry about.

I spent ages a couple of years ago building a spread sheet with the necessary calcs in so that all I had to do was add the distance between the rings, the height above the barrel and the MOA required and it gave me a number and it worked very well for the #2 AI, sadly it looks to be lost. I really should do it again if only for any future projects.

Edit - Robin, I mean shimming the mounts the scope rings fit on so yes you are quite right. I often notice people with a rear ring shimmed above the rail, I have never been happy about such a solution, in an ideal world you would use a tapered shim and lap the rings in so there was no excessive deflection on the 'scope tube.

[Dangermouse]

I would urge you to buy a set of Burris Signature Z Rings, mine came with 10MOA adjustment shims, which actually worked out to be closer to 14. You can also get 20MOA I believe.
Not only do they make adjusting as you require simpler they also protect the scope body.

I have to say that now I have a set I can not see me buying anything else, and amazingly they are mid price.

[url]http://opticswarehouse.co.uk/products.a ... VER+MOUNTS[/url
Certainly cheaper than ruining a set of scope rings or worse the scope tube.

I know you said that you don't like adding shims to your current set up but I have seen a cannibalised set of feeler gauges work in the past. A bit more accurate than a sliced up can of coke - which I also saw once.

DM

[ovenpaa]

This is on the S&L which has a quirky mounting system designed for S&L rings however Apel do a system as well, looking at I am not sure anything else will work without a fair amount of work. The Apel rings are interesting in that the rear ring has the ability to be adjusted to wind zero with physical stops.

I know what I should really do is calculate the angle I need, find a piece of aluminium plate and cut it to the same length as the distance covered by the two ring bases, drill it for the two mount screws the Apels use and then carefully file it to the correct taper, then cut out the centre section.

Not an easy job.....

[Steve E]

You could always do it the easy way and buy a set of Burris Zee rings. These rings have a set of ring liners very similar to a sperical bearing. They also come with a different set of ring liners that are + and - 10MOA. I have had to use these to zero a 'scope on my Paramount actioned Match rifle.

Steve

[Dazz]

Most people use Film negative on either the front ring to raise of on the back ring to lower.