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Scope tube damaged first mounting

Hotrod6.5

Hotrod6.5

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Short story-I purchased a very high quality scope for my latest F-class long range rig and the first time I mounted this scope the top halves embedded grooves into the top of the scope tube front and back.
Long version- My action is a Bordon BRMXD in a new Cerus stock put together by Speedy Gonzales. The rail is one of Jim Borden's 20MOA one piece rails which I have never had scope mounting issues with (I have three of these actions and love them) and the 4 screw rings were purchased along with the scope one year ago when I started the project and are also manufactured and labeled by the same company. Even though the Company's advertising claims lapping is usually not necessary I always do this or at least run my lapping rod dry to see the witness marks and check before installing my new scope. I use a non embedding compound and as I recall the bottom halves of these rings did not take excessive lapping to get trued up. I stop lapping when I get 80% or more contact. I aligned my scope as normal and snugged the tops down with my fat wrench set at 16 inch Lbs which is what I always do and recheck from time to time. I shot the rifle out in Phoenix at the SWN and found myself needing the scope moved back a bout 1/4" so when I got it home I loosened the tops and tried to slide it back-no go-it was locked up so I completely removed the tops and there are now four deep grooves in the top of the tube where the ring tops embedded themselves. I'm thinking this has never happened with any scope ring combination in my life so I contact the company and they say send it in for warranty. I send the scope and the rings and after watching the tracking I did not get a call so after three days I call them and yes they received the scope and looking at the damage they are thinking the replacement tube is going to cost me about $700. They said the bottom of the scope is perfect and the damage was only on the top so why did I not lap the top halves of the rings like I did the bottoms? This turned out to be a long response and in the end I told them if they did not intend to replace the scope just send it back and I would post pictures (and the company I'm dealing with) to folks here on the Forum and see what you guys think. I guess I'm still hoping for a good outcome but we will see. I have 3 Nightforce competitions and have had them mounted and remounted more times than I can remember and have never had any marks ever. I should have just saved some money and gotten another 55X competition. We'll see how this all plays out, but for a scope company claiming "I abused the tube" by not lapping their rings is BULL!
 
yeah! Just threaten them. Usually works well, especially if you appear to be at fault by lapping only half the ring set. I would suggest that leaving the top halves alone is what caused the problem.
The top halves no longer mated true after removing material from the bottoms only.

No offense, but if those rings were round coming out of the box... Figure out who and how they got out of round.
 
I prefer tightening ring caps by feel. Some tubes are thinner than others and softer. I have generally never lapped ring caps because they tend to lay to the scope tube and if the body of the ring was lapped at a slight angle to its original configuration the caps can tilt by that small amount without any problem. I have never marked the top of a tube, and I have mounted quite a number of scopes. I do take a look at cap fit on the tube and round all edges and corners that will contact the tube, on both the ring body and cap. Have you considered the possibility of a malfunction of your torque wrench?
 
With a little less cockiness, I'd say IdahoSharpshooter is about on. Probably would have been in your best interest to lap both entire rings. That's normally what makes the contact perfect. Still hard to believe that a set of rings could be that far out to actually put four creases in the scope tube to the point of denting or damaging it. I suppose your at the mercy of this company and them allowing their warranty to cover an error in judgement. Regardless of the outcome, if you post that this company is default in their replacing the scope and explain how and why the damage occurred, I doubt anyone would blame the company for a faulty scope and cease buying from them again. Scratch this off as a dumb dumb brain fart and move on. We all do it and we all get the bad end of the deal at those times. Good luck and hopefully they work with you on this issue.
 
As I stated before, I am still working with them on the issue and they are consulting the factory about what to do next. I hate to name names until the final outcome is known. I feel like they will probably take care of me but we started off bad when they asked about lapping the tops. Torque is another legitimate question however. I know over tightened screws often damage scope tubes, I have seen several and that is why I use a trusted method to not only apply correct torque but apply it evenly to all screws.

I have used my torque wrench for about 15 years and always relax the torque setting to zero while storing it, I've had zero issues with over torque. I have been a tool and die maker and gunsmith for 40+ years and kinda have a feel for proper torque and the rings were not over torqued. I do all my own metalwork on my builds including chamber work and re-barreling and bedding, Ive been at this for awhile.
I have guns with just two screws per cap with the same 16-18 inch Lbs of torque on them and still never had marking issues or a scope move in the rings when lapped on the bottoms only. Ring caps that are machined true as to radius are supposed to conform and more or less float to the center and saddle the tube using the small amount of give or wiggle room on the screws and the clearance holes in the top cap to do this. I have done a lot of lapping in my time and this is a slow way to remove anodized aluminum and I sincerely doubt I lowered the bottom half of the rings by more than .001"-.002"
Anyone want to tell me how you go about lapping the top half (read flimsy and flexible compared to the bottoms) of a set of rings?? anyone? if you mount them to the bottoms and try to lap them it will lock up your lapping rod and if you back off the screws enough to get the rod to move back and forth it would rock the rings causing a bell shaped profile on the tops of the caps front and back and would only make contact in the middle when done. If you try to lap the top halves off the bottoms and one at a time it would be even harder to lap a true radius that is also centered in the bottom halves. Think in Pairs and in perfect alignment, this would be impossible for any gunsmith to do.. and that is why only the bottoms are lapped because they are mounted to a common plane (the rail) and torqued down to that rail in the same location as when on scope is setting in them and tops are installed. So to answer the question of why I did not lap the top halves is looking at a way to make this my fault, and kind of an uninformed question in my opinion.
 
Hotrod6.5 said:
As I stated before, I am still working with them on the issue and they are consulting the factory about what to do next. I hate to name names until the final outcome is known. I feel like they will probably take care of me but we started off bad when they asked about lapping the tops. Torque is another legitimate question however. I know over tightened screws often damage scope tubes, I have seen several and that is why I use a trusted method to not only apply correct torque but apply it evenly to all screws.

I have used my torque wrench for about 15 years and always relax the torque setting to zero while storing it, I've had zero issues with over torque. I have been a tool and die maker and gunsmith for 40+ years and kinda have a feel for proper torque and the rings were not over torqued. I do all my own metalwork on my builds including chamber work and re-barreling and bedding, Ive been at this for awhile.
I have guns with just two screws per cap with the same 16-18 inch Lbs of torque on them and still never had marking issues or a scope move in the rings when lapped on the bottoms only. Ring caps that are machined true as to radius are supposed to conform and more or less float to the center and saddle the tube using the small amount of give or wiggle room on the screws and the clearance holes in the top cap to do this. I have done a lot of lapping in my time and this is a slow way to remove anodized aluminum and I sincerely doubt I lowered the bottom half of the rings by more than .001"-.002"
Anyone want to tell me how you go about lapping the top half (read flimsy and flexible compared to the bottoms) of a set of rings?? anyone? if you mount them to the bottoms and try to lap them it will lock up your lapping rod and if you back off the screws enough to get the rod to move back and forth it would rock the rings causing a bell shaped profile on the tops of the caps front and back and would only make contact in the middle when done. If you try to lap the top halves off the bottoms and one at a time it would be even harder to lap a true radius that is also centered in the bottom halves. Think in Pairs and in perfect alignment, this would be impossible for any gunsmith to do.. and that is why only the bottoms are lapped because they are mounted to a common plane (the rail) and torqued down to that rail in the same location as when on scope is setting in them and tops are installed. So to answer the question of why I did not lap the top halves is looking at a way to make this my fault, and kind of an uninformed question in my opinion.
Click to expand...
It's possible the ring caps were mismatched to the base rings. Even lapping may not have helped. It just seems really odd that the tube was damaged that badly from not lapping. I know most people don't lap their rings and I've never heard of tube damage other than ring marks. I've been lapping almost since I started shooting regularly and many times it wasn't necessary. Many top end scope companies are picky about warranty coverage. Most lower priced companies scopes unconditionally guarantee their scopes. Seems like it should be the other way around. Post your results. Curious if the outcome.
 
Hotrod6.5 said:
Short story-I purchased a very high quality scope for my latest F-class long range rig and the first time I mounted this scope the top halves embedded grooves into the top of the scope tube front and back.
Long version- My action is a Bordon BRMXD in a new Cerus stock put together by Speedy Gonzales. The rail is one of Jim Borden's 20MOA one piece rails which I have never had scope mounting issues with (I have three of these actions and love them) and the 4 screw rings were purchased along with the scope one year ago when I started the project and are also manufactured and labeled by the same company. Even though the Company's advertising claims lapping is usually not necessary I always do this or at least run my lapping rod dry to see the witness marks and check before installing my new scope. I use a non embedding compound and as I recall the bottom halves of these rings did not take excessive lapping to get trued up. I stop lapping when I get 80% or more contact. I aligned my scope as normal and snugged the tops down with my fat wrench set at 16 inch Lbs which is what I always do and recheck from time to time. I shot the rifle out in Phoenix at the SWN and found myself needing the scope moved back a bout 1/4" so when I got it home I loosened the tops and tried to slide it back-no go-it was locked up so I completely removed the tops and there are now four deep grooves in the top of the tube where the ring tops embedded themselves. I'm thinking this has never happened with any scope ring combination in my life so I contact the company and they say send it in for warranty. I send the scope and the rings and after watching the tracking I did not get a call so after three days I call them and yes they received the scope and looking at the damage they are thinking the replacement tube is going to cost me about $700. They said the bottom of the scope is perfect and the damage was only on the top so why did I not lap the top halves of the rings like I did the bottoms? This turned out to be a long response and in the end I told them if they did not intend to replace the scope just send it back and I would post pictures (and the company I'm dealing with) to folks here on the Forum and see what you guys think. I guess I'm still hoping for a good outcome but we will see. I have 3 Nightforce competitions and have had them mounted and remounted more times than I can remember and have never had any marks ever. I should have just saved some money and gotten another 55X competition. We'll see how this all plays out, but for a scope company claiming "I abused the tube" by not lapping their rings is BULL!
Click to expand...

I had a problem like that with IOR 35mm rings and one of their 6-24's. Mostly just the jagged edge of the crappy rings scratching the crappy finish on the scope. Just sharing some old discontent so you don't feel so alone.
 
284winner said:
It's possible the ring caps were mismatched to the base rings. Even lapping may not have helped. It just seems really odd that the tube was damaged that badly from not lapping. I know most people don't lap their rings and I've never heard of tube damage other than ring marks. I've been lapping almost since I started shooting regularly and many times it wasn't necessary. Many top end scope companies are picky about warranty coverage. Most lower priced companies scopes unconditionally guarantee their scopes. Seems like it should be the other way around. Post your results. Curious if the outcome.
Click to expand...
I think you might be right about the mismatching but from a bit different perspective. The deepest engraving on the top of the tube is from the middle joint up to about 10:30 and 1:30 which could indicate the cap was pulled in towards the middle when the torque was applied. Im not sure how a set of $160 + rings could be machined this far out but crap happens I suppose. When I laid the tube into the bottom halves when I installed the scope everything fit and slid fine and the tops did not pop down or go on tight either just laid down nice and saddled the tube-- all very normal and no burrs or dings on the tops. I always keep all four parts in the same orientation as they come to me in case there is a machining issue. It is unimaginable that the scope tube/body could be soft and not heat treated properly. Heat treating would involve the entire blank and would be in T6 condition throughout. I have machined a lot of aluminum and if this were the case the tolerances would be wild and they would have caught this very early in the inspection process.
 
Hotrod6.5 said:
I think you might be right about the mismatching but from a bit different perspective. The deepest engraving on the top of the tube is from the middle joint up to about 10:30 and 1:30 which could indicate the cap was pulled in towards the middle when the torque was applied. Im not sure how a set of $160 + rings could be machined this far out but crap happens I suppose. When I laid the tube into the bottom halves when I installed the scope everything fit and slid fine and the tops did not pop down or go on tight either just laid down nice and saddled the tube-- all very normal and no burrs or dings on the tops. I always keep all four parts in the same orientation as they come to me in case there is a machining issue. It is unimaginable that the scope tube/body could be soft and not heat treated properly. Heat treating would involve the entire blank and would be in T6 condition throughout. I have machined a lot of aluminum and if this were the case the tolerances would be wild and they would have caught this very early in the inspection process.
Click to expand...
Human error when machined and packaged.
 
nor mine. Since I have never ruined a scope mounting it (started in 1965) , I think my approach has value.

I put the bases on and torque them to specs. I let them sit on the action a day, then retorque from loose back to specs with a dab of what ever the color du jour of the wife's nail polish shade is. Then I lay the ring bottoms on, put the upper halves on and 4-stage X-pattern tighten them to spec. I measure the ID to see how much, if any, difference there is from one inch and perfectly round. Then I re-torque (a third time) and do what ever minimum amount of lapping is necessary to true them.
Then, the scope gets mounted.
This approach has worked EVERY TIME for me.
 
You lapped the rings, torqued the rings and shot the rifle and the scope moved in the rings.....has anyone thought to mike the scope tube diameter yet??? Rodeo's aside, I have seen scope tubes under size. Usually, you have enough "clamp" or squeeze with most rings that it doesn't matter, but it can be enough to cause this problem. Depending on the rings, how much they were lapped and the scope tube diameter.
Also, using a given torque value that worked for other rifles can be arbitrary when you consider the possibility of things like more recoil, a heavier scope, lighter rifle, etc. maybe you simply need more torque on the rings???
 
Hotrod6.5 said:
Several stages and in an X pattern. Like I have said this is not my first rodeo.
Click to expand...

Of all the rings I've used I'm most impressed with ARC rings. They wrap around the tube more so than squeezing down from the top or sides like other rings do. The clamping force is distributed more evenly around the tube than other ring designs which grips the tube very well.

Analogy -Picture an egg for a moment. If you wrap your hand fully around the egg and squeeze it hard to break it (like ARC rings - tube), it takes much more force to break it than it does to push into the egg from the sides with your fingers(common ring styles). Also that egg would require much more force to remove it from your hand vs just squeezing it in from the sides(tubes slipping in rings due to recoil).

I had a pair of Nightforce steel rings on my 375CT and a NF 5.5-22x56 scope on top, I noticed the tubes finish being marred from slippage, I torqued the ring screws harder deforming the tube a little, the scope still slipped, VERY aggravating!!!

The scope still worked fine but I sold it/cheap and bought the same scope in mil this time and also bought a pair of ARC rings, no problems whatsoever and when that scope was sold the tube looked like the scope had never been mounted.

I'm on my 4th pair of ARC's now and have no hesitation recommending them.
 
msinc said:
You lapped the rings, torqued the rings and shot the rifle and the scope moved in the rings.....has anyone thought to mike the scope tube diameter yet??? Rodeo's aside, I have seen scope tubes under size. Usually, you have enough "clamp" or squeeze with most rings that it doesn't matter, but it can be enough to cause this problem. Depending on the rings, how much they were lapped and the scope tube diameter.
Also, using a given torque value that worked for other rifles can be arbitrary when you consider the possibility of things like more recoil, a heavier scope, lighter rifle, etc. maybe you simply need more torque on the rings???
Click to expand...
You missed the first post where i described the rings embedding into the top half of the tube and would not let my scope slide back even when the screws were completely backed off. I did a search for my particular scope make and model here on the forum and found most used scopes sold had the very same ring marks embedded into the tube. And for the record my rifle is chambered in 6.5X47 Lapua which is not a hard recoiling rifle. I'm hoping to hear something soon and will post the response from the company either way.
 
Some tube on br scopes are very thin to save weight. They can be dented even with a normal amount of torque. When to tighten a ring it tends to pull in and that's where the dent usually happens, right at the joint.
 
I think March scopes with 34mm tube have a 4mm thick wall instead of the 2mm thick wall on their 30mm tube models. Also, their rings are actually relieved where the two halves meet, if I remember correctly.
 
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