Scope shim?

[Kungfugerbil]

Morning all,

Following a recent discussion about rimfire benchrest and the suitability of certain targets, I thought I would have a test fit of my new scope (or giant shiny sex toy as one of the lads called it...) to my previous prone rifle.

Rifle: Anschutz 1613 in supermatch stock
Scope: Falcon T35s fixed mag benchrest reticle

It works Ok - going clear on a BM2510 without difficulty on my first card - but there is still lots of playing to get the setup right. I'm also making up a front rest rather than a wobbly wire bipod and lump of 1x2...

With the scope I am literally on the last click of vertical travel upwards to get on zero at 25m. I will only be shooting at 25 and 50 but need to introduce some more adjustment. Having never had this issue before, can I check with those more knowledgeable...

I believe I need to shim the rear to effectively point the scope down, bringing the muzzle up. Is that right? The mounts attach directly to the dovetails so I guess I need to shim inside the saddle of the scope ring? I've got a pack of shim steel so should be able to find the right thickness.

For the benefit of Ste (and with tongue firmly in cheek) this is what it looks like so far...

[bradaz11]

wouldn't you raise the front of the scope, to allow you to wind down?

[Kungfugerbil]

wouldn't you raise the front of the scope, to allow you to wind down?

I don't think so - if you raise the front then the bore will be pointing below the target and bullets impact low. As I'm out of upward travel, I wouldn't then be able to get it back on target.

This is my naive thoughts anyway - my usual sights are iron or a hole in a Perspex disc!

[Pinguino]

If you physically raise the front of your scope with a shim (without changing what you have dialled in) you will end up with a bullet POI LOWER (ie. closer) when re-aiming to the same place.
If you are at the max on your TOP elevation clicks, raising your scope with a shim will mean you are looking even higher and therefore you would have to click down to get to the same point as before, so raising the front of the scope gives you additional elevation clicks to play with.

[Kungfugerbil]

^ The first part of that tallies with my understanding, but the second doesn't follow (to my mind!)

If I shim the front up and change nothing else, my rounds will impact low. I don't have any more upward travel to bring them up to target as I am in the max.

If I shim the rear and change nothing else, my rounds will impact high. I then have a few full turns to bring the rounds down to target....

[Pinguino]

Are we both discussing the same thing or are we at odds with POA and POI.

[Pinguino]

So as not to confuse things - I assume the original ask was that while Kungfugerbil could hit as close as 25 yards - he wanted a little leeway to get a bit closer and have a that flexibility. Are we agreed?

[bradaz11]

If I shim the front up and change nothing else, my rounds will impact low. I don't have any more upward travel to bring them up to target as I am in the max.

I could be wrong... but if you are impacting low, wouldn't you click the scope down?

[Kungfugerbil]

I could be wrong... but if you are impacting low, wouldn't you click the scope down?

It might be terminology. My scope has 'up' and 'down' directions - they refer to the direction you move the POI. So if I'm hitting low, I click it toward 'up', the bullet hits higher.

My problem is that mounting it out of the box I was hitting waaaay low. I clicked it 'up' to the max and I'm on target (just!) at 25m. I want to change this for two reasons:

1. I would like the scope to be in the middle of the adjustment range at the usual distance - 25m - so there is both up and down movement available
2. I will also be shooting at 50m - so I need the ability to raise the POI.

As it stands I have no ability to move POI up as I'm at max click. My reasoning for shimming the rear is that it will lower the POA and hence raise the POI.

Hope that makes sense!

[TattooedGun]

Morning all,

Following a recent discussion about rimfire benchrest and the suitability of certain targets, I thought I would have a test fit of my new scope (or giant shiny sex toy as one of the lads called it...) to my previous prone rifle.

Rifle: Anschutz 1613 in supermatch stock
Scope: Falcon T35s fixed mag benchrest reticle

It works Ok - going clear on a BM2510 without difficulty on my first card - but there is still lots of playing to get the setup right. I'm also making up a front rest rather than a wobbly wire bipod and lump of 1x2...

With the scope I am literally on the last click of vertical travel upwards to get on zero at 25m. I will only be shooting at 25 and 50 but need to introduce some more adjustment. Having never had this issue before, can I check with those more knowledgeable...

I believe I need to shim the rear to effectively point the scope down, bringing the muzzle up. Is that right? The mounts attach directly to the dovetails so I guess I need to shim inside the saddle of the scope ring? I've got a pack of shim steel so should be able to find the right thickness.

For the benefit of Ste (and with tongue firmly in cheek) this is what it looks like so far...

Good shootin' :)

if you can do it consistently you should do really wlel in the leagues :)