Shimming a scope

I dropped an Element Optics Helix on my .223 to shoot some groups. I wanted to test a few loads for accuracy.
It was previously on my .308. After about 20 rds I finally figured out it was about a foot low and a foot right at 25m.

Its so far out I don't see the point of putting it on that rifle but it got me thinking. If I was to zero it, what would be the best way?
If it was a standard 3-9 hunting scope I would set it and forget it.
But because its dialable, I'm just going to use up all the adjustment within the scope to get on paper at 100m.

One foot at 25m is four feet at 100m.
Four feet is 122cm and one click is one cm, so to get on target is 122 clicks.
The adjustment range is 18.9 MRAD, there's not a lot left over to dial with.

I figure the only way to make it work is to shim the scope in the ring.
The shim should be in the forward ring in the top right quadrant. That should center the scope more.

I'm pretty rusty at shooting long range so I may have missed something obvious, I am curious to hear what the pros think :thumbsup:

Attachment 261348

Attachment 261349

Sounds like there is something amiss with your rings or rail/bases, are you sure they are correctly engaged? A picture might help.

In the bad old days of sporterised mausers and the likes of bad American QC this was a problem that arose occasionally but I haven't struck a rifle like it in years

What mounts are on your rifle? Could you put a picture up please?

Mount is an Aero Precsion, its not the best. I find it twists the scope as you tighten it up. So there's a bit of guess work required to get the scope level in it.
It should work well enough to test some groups though.

Attachment 261352

That almost appears to be hitting the piccy rail at front which would poke scope up,make shots go low???

It should not "twist the scope" bring it tomorrow and the "brains trust" will sort it, failing that Jordaan carries a large range of hammers for delicate work to major modifications. There no problem that can't be solved by hitting it enough times.

Shimming is almost akin to a "bush fix". I've done it before and it works, but always felt that it was just something else to go wrong.
Like Tentman says, the mounts and rings might needs more attention; they shouldn't align the scope so poorly that you need to shim.

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Originally Posted by Sh00ter

I figure the only way to make it work is to shim the scope in the ring.
The shim should be in the forward ring in the top right quadrant. That should center the scope more.

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If you do shim then as far as I remember the shim should be on the back ring bottom (to bring the scope down so lifting the rifle to aim) and also on the back ring side right to bring scope right so you shift the point of aim to the left.
It's unusual to have a one-piece mount that is not straight unless it's been dropped.

Buy some nice high rise independent scope rings.Spread the scope rings apart as far as you can from back of scope to front of scope.Gives more stability of scope and better alignment.

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Originally Posted by Micky Duck

That almost appears to be hitting the piccy rail at front which would poke scope up, make shots go low???

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I removed the rail cover. It's just soft rubber and the mount was in the proper position, but it might have been causing some interference.

Ive shimned a lot of air rifle scopes as on some of them you cant adjust low enoungh for the close range. Its worked fine. Might pay to try your rings front to back and turn them 180 as well. A colometer would be handy if you have one.

Just an idea.
Have you tried mounting it in the independent rings that came with the scope?
This will ID if its a rail or mount issue.
I have the same scope (still in the box)
NRF.

Attachment 261362

This is the normal set up with a strike eagle in the aero mount shooting belmont 62grn. I use it for goats and service rifle and it works well enough. I wanted to try some different ammo so chucked on the helix for more magnification. Maybe the rail cover is part of the problem, but it works fine with the strike eagle.

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Originally Posted by Marty Henry

It should not "twist the scope" bring it tomorrow and the "brains trust" will sort it, failing that Jordaan carries a large range of hammers for delicate work to major modifications. There no problem that can't be solved by hitting it enough times.

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Thats not a bad idea I've been meaning to go for a while just keep getting caught up with work. Jordaan can keep his hammers in his truck, things aren't that bad yet, lol. Although fixing it with black powder could be interesting ;)

What's the bolt rifle? (Just being nosey for something I don't recognize off the bat)

.308 ruger scout with a bloody annoying loudener

5 , 10 , or 20 MOA riser on the rail? pro: no shimming or added tension on scope , con: one extra part to worry about movement and may also lift the occular uo to an uncomfortable position......
spitballing as im no expert

yes I have seen shim jobs and they belong in the realm of Mr sledgehammer fix it f#%K ups - okay I suppose on a chinese air rifle - no keep looking - something wrong there you will find it and some great advice on here where to look

The old school non image moving scopes were a pain.
I only have one and tried it very briefly on a P14 308 ex target rifle..
Parker hale rings and bases.
These needed shimming to keep the reticle mostly centered.
I didn't try but the reticle was a long way up towards one corner of the scope.
Was told by the previous owner they had to shim the bases

Could look at the Burris signature rings with the
Shims that can be adjusted for offset
WILHELM ARMS & OPTICS Has a pair of extra high
30mm ones left on his price list
RickWilhelm@proton.me or richard.wilhelm@slingshot.co.nz
$157 last of his stuff left over from his old shop stock

Can adjust the inserts around to dial in a scope to get the most travel
Out of the scope

Burris rings are your answer, or if be inclined to ship the base(I'd it's even straight)
Swimming the scope tends to put point pressure on the tube, which I not how it should work and could damage tube.

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Originally Posted by csmiffy

The old school non image moving scopes were a pain.
I only have one and tried it very briefly on a P14 308 ex target rifle..
Parker hale rings and bases.
These needed shimming to keep the reticle mostly centered.
I didn't try but the reticle was a long way up towards one corner of the scope.
Was told by the previous owner they had to shim the bases

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Very old school ones used to have a wedge prism in a circular holder in the front of the scope. Turning this a certain way achieved the 'coarse' adjustment and then you fine tuned the thing using the adjustable mounts. Very agricultural, painful in fact.

I think everyone has pretty much nailed it though - if you have to shim a scope setup on a platform like that something isn't right. It should be within ballpark as soon as it's bolted up if the scope's reticle is centered and there's nothing wrong with the rest of the setup. The only times I've encountered issues like this, there has been a mechanical problem like a mismatch in components, a part not correctly mounted, something wrong in the assembly of the rifle action or barrel, or an interference in the fit between something in the mounting system.