Help with sight alingment required!!

[drummer]

I have just been given a new Rhino 6 - 24 x 50 Mil Dot AO IR .... not the best of scopes I've been told but heh it was a present!!

I fitted it to my .177 AA400 and tried it out at the range @ 35 yards yesterday but even with maximum adjustment on the elevation turret it was still shooting really low. The Simmons scope I took off had no such problem.

Can anyone advise on how I might resolve this, I was told shimming up the mounts should cure it .... What do I have to do?

Any help much appreciated!!!

[GHMikeB]

Take the sight out of the mount, put a piece of card the width of the mount front to back and long enough to go across the bottom but not too far up the sides as this would make it too tight sideways, in the rear mount so that the sight will look slightly down. Replace the sight and the tops of the mounts and try it, you may need another thickness, trial and error being the answer. Obviously the same applies in the other direction, the card just goes in the front mount in that case.

[Martin]

Dont use card or anything that will compress over time, you're asking for wandering POI that way.

Film negative is the stuff to use for shimming.

Mart.

[GHMikeB]

Good point, I was thinking about the fact that card would be affected by humidity, but could not think of an alternative off the top of my head.

[Keef]

There is an alternative to the card/film negative packing under the rear mount, as this method will put your scope out of line with the bottom of the front mount.
Put one layer of cling film around the areas of the scope that comes into contact with the mount. Centralise the reticule in the scope both for line and elevation.
Get some epoxy putty and mix up a small amount, roll it into a thin strip. Put this into the base of the front and rear mounts so the strip covers the bottom one third across the width. Place the scope in the mounts and put the top caps on and pinch them onto the scope. At your normal zeroing range start shooting and by tightening down the top caps zero the scope for elevation. If you choose a putty with a longish or adjustable curing time this will give a longer period to set up the zero.
Once the putty has cured take the set up apart, remove the cling film and reassemble.
The alternative to setting the scope ret central and setting up at your normal zero range is to centralise the ret and then turn it down 1 turn. Then zero at the distance that the pellet is the highet on the trajectory. This will mean that if you dial for range the zero is set at the highest point and you will only ever dial up from that setting.
Remember that the scope does not need much putty to alter the point of impact(POI) of the pellet considerable. If your mounts are 100mm apart, 0.5mm of putty will move your POI by 250mm at 50 meters.
If you change the distance between the mounts you will have to do the set up again as the angles will change between scope and mounts/putty.

[drummer]

Thanks for the replies Guys

I'll try the film negative first, then if OK maybe Keef's later.

[Gwylan]

Keef... I haven't heard that one before. Seems a bit drastic, as it would be permanant, but it would protect the tube from damage. You learn something new every day on the BBS...!
Gus

[sniper22]

i pack my scopes with brass shim, available from engineers suppliers.

[Keef]

I claim no credit for the system.
If memory serves I read about in an article many moons ago by Nick Jenkinson in one of the airgun mags. It is permanent but does mean that the scope does not sit on the front edge only of the front scope mount base.
I have not used it as if I have this problem I make a set of adaptors to go between the mounts and the rifle dovetail with a taper machined in but the epoxy putty is a cheaper method.

[sphexx]

I claim no credit for the system.
If memory serves I read about in an article many moons ago by Nick Jenkinson in one of the airgun mags. It is permanent ...

Maybe I am missing somethng but can't you sandwich the epoxy between two layers of cling film and make a removable version?

[Mr.Fixit-Norm]

Hi,

coincidently I'd just been looking at these on the Nikko Stirling site. No idea how much they are but look like an excellent idea.

http://www.nikkostirling.com/

click on `mounts' on the site and it's the first one to come up.

Norm

ps i've used the film shim idea in the past and it works fine, usually only needed either 1 or 2 layers.

[Keef]

If I was opting for the adjustable mount route I would go for the B Square type. I have a set on my FT set up and they allow me to set up a droop on the scope but more importantly they allow me to set up for line as well. With this I can set the scope up so that it corresponds to the bore axis for alignment and parallelism or in my case a slightly bent scope.

[Gwylan]

If I was opting for the adjustable mount route I would go for the B Square type. I have a set on my FT set up and they allow me to set up a droop on the scope but more importantly they allow me to set up for line as well. With this I can set the scope up so that it corresponds to the bore axis for alignment and parallelism or in my case a slightly bent scope.

BSquares are good, they get over the elevation problem, and any crossover.
Gus

[Martin]

Tim Finley did a recent article in shooting sports on FT scope set up, including the epoxy mething, id be happy to scan it if someone wanted to see.

Mart.

[drummer]

Martin

Can I take you up on the scan offer

Cheers
Gerry