Scope mounting - done right? gone wrong

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I bought a set of genuine CZ rings for a CZ 452. The CZ rings come in two pieces, a base that clamps onto the CZ receiver rail, and the rings that are attached to the base by a screw installed through from the underside of the base. I believe the idea is to provide a smidgeon of lateral alignment if needed. Set it up with the aligning bar from my Weaver scope mounting kit; lightly lapped the bottom part of the saddles. On these rings, the bottom part of the ring (that I am calling a saddle) takes up much less than 180 degrees - perhaps 130 or 140 (did not measure). This means the upper strap of the ring takes up much more than 180 degrees of the scope tube diameter - say 220 to 230 degrees. Tightened everything up with the Weaver torque wrench. All seemed good. Worked well. Just about puked when I took the thing apart last night to swap the scope onto another rifle - the lower edges of the upper straps had creased the 1" scope tube (all four of them had dug into the tube). I am getting 25.4 mm as diameter on the rings, so really at a loss as to how this went wrong, when I believe I had followed proper steps. What did I miss?
 
You used a torque wrench, but didn't specify the lbs used. If you tried for the correct number, I suspect you'd mention "I torqued it to 22lbs just like the manual said", etc.

By your own admission, the rings crushed the scope tube.

Really what else could it be?

*cough,cough*
 
I have 3 cz's (varmint455,455 lux,452 scout)all 11mm dovetails with scopes and didn't lap any and they all shoot under 1" all day long with bulk ammo. Leopold rings & Warne rings. Warn say don't need lapping on their web site.didn't research Leopold site. Have had the scopes on and off a few times and there are no marks. Warne also designed with one side less than 180 deg contact. Mueller and Leopold scopes. 30mm and 1". Mant on rimfere central don't lap.

That's my 2¢

R
 
What scope was it, if it was anything other then a vortex then sorry to hear about that, also curious if your torqued things down to far. A real bummer, but just because things are expensive or made in Europe doesn't always mean they are superior to domestically made or cheaper brand stuff, game reaper mounts may have worked well for example.
 
1. Torque is determined by screw size, 6/48 about 23 in/lbs, 8/40 about 28 in/lbs.
2. I have not yet found a set of steel rings that did not need to be lapped.
3. Aluminum rings should not be lapped as all you do is charge the ring with lapping compound and lap your lapping bar.

The marks you created were caused by not lapping and or over torquing.

Scott
 
I have done many, many CZ and BRNO of all kinds.

First - the CZ rings are very well made and fit their receiver dovetails like they are supposed to unlike some others that may or may not have the correct dovetail shape or the correct stud to fit into the side notch of the receiver. Some rings of course are not made for the CZ dovetail at all.

Do not let someone convince you to drill and tap the receiver.

The way I have always done the CZ/BRNO fits is to check to see that the rings and scope tube diameters are meant for each other. 26 mm, 1 inch, 30 mm rings and scopes abound in the euro world. There are other sizes that may turn up as well. Recent manufacture tends to be either 1 inch, 26 mm or 30 mm.

Once I find my proper placement for eye relief, I "snap" the rings together on the scope (you may wish to use a thin tape to protect the tube for that upper ring that needs to "snap" over centre of the tube) I screw the whole thing together to make sure the screws all fit nice and are not too long into the receiver or any other issues.

I keep the screw that goes up from underneath the base into the rings just slightly loose for this fitting. I do a quick bore sight check to see if everything lines up close to line of site.

I rarely lap.

Once everything fits with the CZ type rings and bases, and it is snug enough for everything to stay in place, I then take off the whole of the scope and rings from the receiver of the rifle and tighten the under screws into the rings, Sometimes on the big bores I use some purple locktite on those screws.

(The thing about these CZ/BRNO rings is that the screw up from the base into the bottom of the rings must be allowed to find its center when the rings are on the tube. If you have that base screw too tight so the rings cannot move and try and then put the tube into the rings and then clamp it all down - you could get a side wrinkle in the tube.)

Then it all goes back on the rifle and you snug up the bases onto the dovetails of the receiver.

At that time you get you crosshairs vertical and using a good torque driver in INCH LBS - you slowly snug each screw to the the rated spec --- it does not take much. I think they are 3mm screws - 20-21 inch lbs for a .22 should be good

I suspect (only guessing) that you crushed it down too far, or had the rings tight on the bases but the rings were slightly off of perpendicular to the tube. A very common trait among guys like me. Normally I used to snap screws off instead of wrecking a scope - but over the years I have become more gentle and precise.

It sounds complicated but it is not.

BRNO has been using this system for some 70 years or so. Any 11mm dovetail will fit another set of rings and bases for that size. Same with the 16 or 19 mm dovetails. I switch scopes by unclamping one base for a ZG47 and putting it on a BRNO 600 or CZ 550 - they all fit in that size range. It was their Picatinny rail of its time.
 
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Thanks for replies. Farshot - what you described is very close to what I did - I had actually used the lapping bar (not the pointed "aligning" bars) to align the saddles and rings once the bases were tightened to the 35 inch lbs on the torque wrench. The ring screws were tightened to 20 inch pounds, working around the set of 8 a bit at a time (like one torques in a cylinder head). As hopefully you can see in the pictures below, all four edges of the rings "bit" into the scope tube - almost as if tightening the ring screws caused the bottom ends of the rings to press inward. I was removing a Mueller APV intending to mount a Leupold VX-11 rimfire, but not going to do so until I can figure out how I damaged the Mueller scope tube. Any more thoughts??

Creases on scope tube:


Creases on the other side:


A picture of what I meant by the saddles taking up much less than 180 degrees of the scope tube:
 
can you measure the scope tube diameter?

I must admit it looks strange.

I have used those exact rings for 20 years with no issues.
 
That does look strange, and not what i pictured.

I wonder if thats a quality control issue

Sorry to see your scope like that, its a bum deal
 
Sometimes ring manufacterers provide those little stickie back tape inserts
to put in the rings and scope tube.
On occasion these get left out which may cause this?
 
That is really weird, not what I was expecting either, I had a bit of that with a leupold vx2 and over tightened rings of the same style before. For the rings to make a dent like that I think the lower section would have to be a tighter radius then one inch.

Moving forward, I'd grab a 1" lapping bar, and then lap the rings slightly, the wear shown on the rings will tell you if they are too tight on the scope creating pinch points.

Or... if the bar doesn't drop in fairly snug to the bottom of the saddle, I would contact the manufacturer and let them know you have a damaged scope because of their product and would expect them to cover damaged scope and you can lap the rings properly for its replacement, you would also need to check the scope diameter with calipers to make sure it is within spec. The manufacturer may want some pictures or you to return the rings for inspection, but it would be easier to just lap them and get another scope.
 
I am guessing that the rings were less than an inch, or that the Mueller scope has a 26mm tube diameter.

I lean to the diameter of the scope given the pinch pattern
 
Ouch!

How much of a gap on those rings between top and bottom? Was it equal on both sides? Sure looks like over tightening to me.

OK, I found the rings. Weird. Just putting them back together you should see how they pinched.

19193.png
 
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Those style of rings have been used for over 50 years - I have a dozen of them in use and they have never pinched a scope.

A good thing about them is that they don't rotate a scope as you tighten them.

The other good thing is that they are made for the BRNO/CZ line by the same people who make the rifles. So they fit the rifle as they should.

and btw...there are many, many 26 mm bodied scopes out of Europe. They did not use 1 inch until relatively recent times.

Perhaps the top halves of the rings did not go back on the best fit way fro the way they came off each bottom half. Should not make a difference I know, but maybe with this particular set, it did make a difference as to the mating of the halves.
 
I wonder if your torque wrench is whooped?
If the tubes are 1" and the rings marry up to them, maybe the
torque wrench is releasing to far along the pre-set release.
 
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