FYI.....Scope mount screw torque specs from UTG mount.

[Yak54]

All very interesting & very informative for me.  Thanks for taking the time to post this info Ed.  It tells me to stay away from the narrow width rings.  And I think it proves that you have trained your fingers very well over the years so much so that when holding an allen wrench they are calibrated in inch pounds !

[T-Higgs]

"Torque" is an interesting measure with many variables.  Clean threads, dirty threads, gun oil in threads, Molly in threads, ultimox,  all change the clamping pressure. It really measures resistance whatever the resistance may be caused by. Minutiae maybe, but interesting.  In the past, I have installed scopes with the "crank that SOB down" mentality thinking that any change in poi was surely do to optic movement😕.  I would use the long side of the Allen wrench and have never crushed a scope tube (lucky for me) that I know of.  I think there might be something to the cheap heavy scope theory.  I would torque the lug nuts on my truck to spec but not my 400$ scope on my 600$ rifle...  I've evolved a bit since then,  contrary to my lovely wife's opinion,  and have become intrigued by that "minutiae" that makes things work well or not so well.  A tiny nick in your rifle's crown can send your pellet in an horizontal swerve that Archimedes would be proud of.  I believe that it only stands to reason, that while trying to eek out every ounce of accuracy in our equipment,  that science, trial, and measure be used.  I love threads like this and believe this is where reliable information is forged.  Keep it coming.  Perhaps a cleaning of the threads with alcohol prior to scope mounting would help for consistent torque values.  I have noticed a change in POI when muzzle weight screws are tightened too tight. Whatever "too tight" is. Time to keep notes.

[T-Higgs]

I'd like to change my last statement. Technically, what I notice is POI change when I use a muzzle weight/muzzle break.  I'm not sure, yet, if it is the amount of torque on the grub screws or not.  I have read that that over torquing can distort the barrel.  I'm just now dealing with this issue in two of my rifles. One is off for a re-crown presently.

[Racer X]

It is important to follow those torque recommendations but I don't know how realistic it is.

When I got my new scope I removed the scope from the rings. Then needed to move the rear ring back. When I turned the Allen bolt the mount fell off.

The plate with two holes that acts as te lower clamp was broken in half. I have been a mechanic for thirty five years and I am a trained watch maker. I know how to tighten screws.

No I did not use a torque wrench so I am at fault. Not because I did not use one but because I have one and did not use it

But the stress of the two blots on an aluminum plate is a lot .

 I bought a BKL mount. Definitly worth the price

[bubba zanetti]

Bubba

No question that Ed knows what he is doing !  Just seems like there isn't much room for error between 10 in. lbs. where the scope moves, and 15 in. lbs. where the tube gets crushed.  And you and I both know that the majority of guys don't use a torque wrench for putting their scopes on, at least not untill now.  But I appreciate your input and the BKL info from their website, for sure !

I do wonder if the brand of scope also enters into the mix. The Vortex Diamondback is a relatively light scope so PERHAPS scope tube material, or even the wall thickness, could be involved.

I'm ATTEMPTING to show the condition BKL states as......
"15.How do I know when the scope tube is properly clamped?
When the oval shape of the ring becomes a circle around the scope tube and no gap is seen between inside diameter of the ring and the outside diameter of the scope tube. Important: Do not close the gap between the edges of the ring (the flat surfaces where the screws are) as this might crush your scope tube! Please refer to our technical data sheet for more information."

Just for grins I took a 1" tube scope and mounted a BKL "double strapper" to it and took a couple pics. This pic shows the top strap with NO screw torque.
Uploaded at Snapagogo.com

Now here is a pic that shows the "circle around the scope tube and no gap is seen between inside diameter of the ring and the outside diameter of the scope"
Personally.......it was very hard for ME to actually SEE at what point the straps are tight to the scope tube, but it does indeed seem that the fit in the second pic assumed "no gap" was achieved at 10 in/lbs of torque..........
Uploaded at Snapagogo.com



Here is another "oddity" with my set of 1" two piece BKL mounts......the anodizing is literally worn away on the front and rear edges of the base saddle.........
Uploaded at Snapagogo.com
Anywhoo.....I really don't know what all this means except to start at 10 in/lbs of torque, shoot a few hundred shots and if the scope shifts in the rings add a couple more in/lbs till the shifting stops.

As a side note....my R9 is tuned to shoot 8.4 grain 4.52mm JSB Exacts at 850ish fps (about 13 1/2 fpe).

Ed:

Not a bad hypothesis that the scope was the issue. Also, the wear marks you have on the rings is why the long range shooting crowd often machine their rings for consistent fitment specific to the scope and rings themselves.

There are always those tiny variances in production, even top notch production, that can come together in the right manner to knock something just out of alignment enough to cause an issue.

BZ