scope slippage

[-=ed]

I'm trying to be very clear in describing my problem, so many of you may feel that much of the information is unneeded, and I apologize for that.

I have a S1k .177 and .22 with  about 300 rounds thru them.
The .22 has a flat rail on top of the cylinder that could be removed, and the .177 has grooves milled into the top of the cylinder.

I have an F+M 4-12/40 scope on each. After a few hundred shots, the stock rings on the .177 just walked off the top of the the rifle to where the rear ring was coming off the at the end of the grooves. The eyepiece was so far back as to make the scope, and rifle, useless. I had them tightened,  and everything "Loctited", but they just did the same thing again.

The .22 was tightened and loctited, but did the same.  I stopped it after an inch, and  had Weaver rings put on it, and tightened as much as thought safe. They are still sliding back also, though more slowly than the stock ones. I am afraid of tightening the rings any more.

Is there something that could be done about this?

Could the rails be roughened, or could they be pinned in some manner?

Or whatever?

[Gene_SC]

Ed

I wrote a solution to this problem with the S1K in the Gamo forum a couple weeks ago. I had the same problem with my .177 S1k.. Could not keep the scope sighted and everytime it was that the scope would be moving back.

Here is my solution. Take a scope mount that has a set screw installed. Find the spot you want your scope to be at. After you get it where you want it, then remove scope and top rings but leave mount on rifle. Take a drill bit just under the size of the set screw hole and drill a small pilot in top of barrel between the dove tail grooves using the mount as your guide. Remove mount and drill down maybe 1/64 th inch. Then take a bottom drill and drill a straight shoulder in the hole that you made. Do not go through the barrel though. It would not hurt anything if you did but for cosmetic sakes don't drill through. Then place your mount over the hole and insert your set screw untill you feel it lock into the hole on your barrel that you just drilled. You can loctite the screw in place if you want. Mount your scope and rings now.  It will never move again...

Gene

Gene

[longislandhunter]

I had the same problem with the S1k .177 and while I'm sure Gene's fix will work just as he said it does, I took a different approach.  I bought a BKL 260 mount (I needed the high mount model for my scope) and once I installed it on my S1k the scope has never moved so much as a micron. This mount has 6 tightening screws, is a quality mount, and has tremendous holding power. The mount doesn't have a stop pin in it,,, the advertising for it says it simply doesn't need one, and I found that to be the case on my rifle. The mount was a little pricey, but for me it was worth it as I didn't want to drill into my rifle. Oh, by the way, the only place I could find that sold the "high mount" model was "Airguns of Arizona".  Nice people to deal with.  Anyway, good luck and good shooting.

[-=ed]

Is there much  slippage of the scope tube in the rings themselves?

[Gene_SC]

I have never noticed any slippage in the scope rings. I use Accushot mounts and they have rubber inside the rings which grip the shaft.

Gene

Here is the cure I use on my Shadow S1k.

Accu shot one pice mount can be had for 12 to 15 bucks, 8/32 cap screws from home depot, this is on the S1k.
 
On  the Shadow 22 it has stop holes in the scope rails so the bigger cap screws are not nessasry
because the mount has a pin drilled in the mount to engage with the holes in the scope rail.

Also I retap the scope tube holder caps with 6/32 cap screws for further holding power.

"note" you just retap the  mentioned holes, no drilling required, they are just right to retap to bigger sizes.