Scope Rotation?

[Methuselah]

Well, leave it to me to have a situation that isn't common.  At least, an attempt to search for scope rotation and scope rotating turned up nothing similar.

I've got a Leapers UTG 3-9x44 SWAT (three knobs, seemingly somewhat balanced weight distribution) that is rotating with recoil.  It's on a Weaver rail, and the rifle screws were coming loose so I loctited the stock, thumblocks, and even the 8 ring screws one at a time after final alignment was verified with a level on the breach block and plumb line down range.

It's not moving forward/backwards, and all the screws are still tight.  It's just rotating in the direction of the windage adjustment!

It could be the last straw for this rifle, it kicks like a mule, was so loudly ringing it hurt the ears to fire it until I filled the buttstock with expanding foam and took care of the screws coming loose.  And now this.  I think it's got about 700-750 rounds fired (Hatsan 125 in .25 Cal).

Looks like three up, and three down on trying to spark a new hobby for me and the kids.  Daisy 880 shot the barrel out of the shroud (really!) and the mfg. replaced it, Diana 34 just shipped to Umarex is blowing the breach seal out of it, and this one.

Any suggestions, anyone seen this before?  (I am considering a lube tune - never did it before but so much recoil..., and now maybe a ring lapping kit in 30mm?  Gee, I wish those thoughts were "last resort"!)

TIA
(not quite as old as) Methuselah

[BenjiHunter]

Could it be that only the reticle is turning?
If so, the scope has had it.

[William]

Is the whole tube turning or just the adjustment knob turning causing it to lose POI left or right?
If the whole tube is turning and the bolts are tight is the thin tape like material still in the rings between the rings and scope tube?
And if it is only the reticle turning then it is broke!

Loctite it all down (including the tube area meeting the caps and rings) and a tune to bring down the recoil!

[Methuselah]

Is the whole tube turning or just the adjustment knob turning causing it to lose POI left or right?
If the whole tube is turning and the bolts are tight is the thin tape like material still in the rings between the rings and scope tube?
And if it is only the reticle turning then it is broke!

Loctite it all down (including the tube area meeting the caps and rings) and a tune to bring down the recoil!

It does have the tape strips, reticle is etched, whole tube rotated, all was loctited, all still solidly loctited, and yes, recoil still shaking my fillings loose.  I dahknow 

[mobilehomer]

It sound like the rings are too large for the tube. Try a different set of rings.

[farrlarr]

It sound like the rings are too large for the tube. Try a different set of rings.

I agree with this.  Do you have 30 mm rings on a scope with a 1 inch barrel?

[Sfttailrdr46]

If the rings are the right ID then the tube should not be happening. That being said a de burr polish and lube tune should cure that problem I certainly solved my scope killer D460 Spun the Reticle on 2 scopes before the lube and tune Just make sire that you se burr and polish the spring ends also

[Methuselah]

Larry,

It's a 30mm tube that came with 30mm rings (Leapers)

Don,

I may have to do that lube tune, or maybe a kit at some point but I just got it and don't want to void the warranty yet as it still hasn't got me fully trained on how it wants to be held or fed (so no idea if it has any issues yet)

Maybe someone local has a service or owns a polishing kit for the rings?  Something like this might help, no? 




Thanks guys.  It appears if I want to avoid spending more on my already amok hobby I may have to shoot it without the scope and see if it ever settles in (only have about 700 - 750 rounds through it).

[William]

Larry,

It's a 30mm tube that came with 30mm rings (Leapers)

Don,

I may have to do that lube tune, or maybe a kit at some point but I just got it and don't want to void the warranty yet as it still hasn't got me fully trained on how it wants to be held or fed (so no idea if it has any issues yet)

Maybe someone local has a service or owns a polishing kit for the rings?  Something like this might help, no? 




Thanks guys.  It appears if I want to avoid spending more on my already amok hobby I may have to shoot it without the scope and see if it ever settles in (only have about 700 - 750 rounds through it).

If you tune it and smooth it out you wont have to worry so much about how it wants held! Besides if it is that hard on scopes then you may never get it to shoot good without first taming the jolts out of it! Voiding the warranty is the least of your worries as of now, due to the fact you can't even shoot it with a scope! If it is that hard on a scope, now may be the time to use that warranty and see if they can shoot a replacement to make sure it doesn't kick like a mule!

Either way you look at it, it is a lost cause! You either tune it and hope for the best or send it back and hope for a smoother one!
After 750 rounds through it and it still kicks like a wild bull it may never settle down enough to shoot properly!

If it was me I would send it back telling them why!

William

[mobilehomer]

Is there a gap between the ring cap and base? If not, you are not getting any compression, which would allow the scope to rotate. There needs to be about 1/32" gap on both sides when the screws are tight.

[Methuselah]

William,

Maybe I should discuss permission to work on it with Hatsan. I did fill the buttstock, but not the smaller chamber in the grip - maybe that would help?

It's prolly mostly noise not necessarily kick (I shot ALMOST a group w/earplugs in...). Hard to gage w/o the help of a more experienced shooter!  Also, never been much for giving up

Ken,

More than a 16th, slightly less than an 8th gap.  Tightened until I felt a slight stretch (back yard mechanic x40 years...)

What gets me is I really don't understand the forces that a vortex driven recoil could exert that could make the scope rotate but not move back to front.

Earlier today I wrote Lepers cs and asked if they would be willing to lap the rings if I sent them.

Also, not being superstitious, but my luck, if the first purchase goes south, a second attempt usually manages to turn out worse.  Murphy and I are bestest buddies

A lapping kit is about $60.  Maybe

[R1]

Would it be possible that only one of the rings are machined too loose?  You could try to loosen up one pair at a time and check if there is any rotation with the other pair tightened down.  Seems odd, maybe new rings are needed?

[R1]

I have a set of 1" scope rods.  One has the pointed ends and the other is a lap rod.  you may be surprised at how little of the ring actually supports the scope tubes when starting to lap them.  I lap all of my rings and have found a lot of inconsistent bearing surfaces and misalignment issues. 

[Methuselah]

Would it be possible that only one of the rings are machined too loose?  You could try to loosen up one pair at a time and check if there is any rotation with the other pair tightened down.  Seems odd, maybe new rings are needed?

Even so, still begs the question why rotation and not rearward movement?  I just can't figure out the forces involved in why it would rotate and not slide.  I know they were tightened according to pattern, and "properly snug", used alcohol and purple Loctite...

[Methuselah]

I have a set of 1" scope rods.  One has the pointed ends and the other is a lap rod.  you may be surprised at how little of the ring actually supports the scope tubes when starting to lap them.  I lap all of my rings and have found a lot of inconsistent bearing surfaces and misalignment issues.

Yup Mike --- regardless of the true dynamics of the ailment, I believe lapping or replacing the rings is likely my best solution.  Lube tune might work just as well, but I think that leaves whatever issue is behind this unattended (and voids the warranty).  Pity is after about three months trying to get it to shoot a decent group I still have no idea if the bad groups are me or the airgun!

Maybe I make the groups sound worse than they are, all I have to compare to is powder burners - it did paint one 5 shot group at 11 yards you could cover with a dime using crow magnums, and quarter sized @ 25 yards with Benjamin Domes ctc, but I expected better.  Of course with the scope rotated it only hits where I put the zero...

I can't help but wonder if anyone else ever had a scope just start rotating, not the graticule, and no accompanying longitudinal movement. If I hadn't seen it I'm not sure I would have believed it could happen.

[R1]

I have seen less than 1/4 of the ring actually touch the scope body/lap rod.  If the rings are only contacting the scope tube in one small area, it could rotate and not move longintudley.  think of a compression fitting on a water line.  It would rotate as a bearing, and not move back and forth as it would be stopped by the pressure on the small bearing area.  I usually remove the tape strips in the rings when I lap.  In my experience, the tape is just a cover up for poorly machined rings.  Also, are the mounts really straight?  There are many variables in scope mounting that need to be addressed to be successful. 

[William]

I have a set of 1" scope rods.  One has the pointed ends and the other is a lap rod.  you may be surprised at how little of the ring actually supports the scope tubes when starting to lap them.  I lap all of my rings and have found a lot of inconsistent bearing surfaces and misalignment issues.

Yup Mike --- regardless of the true dynamics of the ailment, I believe lapping or replacing the rings is likely my best solution.  Lube tune might work just as well, but I think that leaves whatever issue is behind this unattended (and voids the warranty).  Pity is after about three months trying to get it to shoot a decent group I still have no idea if the bad groups are me or the airgun!

Maybe I make the groups sound worse than they are, all I have to compare to is powder burners - it did paint one 5 shot group at 11 yards you could cover with a dime using crow magnums, and quarter sized @ 25 yards with Benjamin Domes ctc, but I expected better.  Of course with the scope rotated it only hits where I put the zero...

I can't help but wonder if anyone else ever had a scope just start rotating, not the graticule, and no accompanying longitudinal movement. If I hadn't seen it I'm not sure I would have believed it could happen.

I had my Scope rotate on my Springer (Benjamin Titan NP) and after I got that stopped, it broke the reticle loose and it rotated. At first it was just moving back. I replaced the scope with a better one and loc-tited everything down, have not shot it much lately but it is still holding POI. I did however change to a different set of rings, which I think helped.

I would love to have a good smooth shooting Springer, but after shooting my PCP's it is hard to justify taking a chance in buying one (a good one) and then not liking it. I think that if I did purchase a springer or Gas Ram it would have to be maybe a Diana or something in that class. I think this would be my choice Diana RWS 54 Air King. Although I do like the other Diana's as well!

Anyway good luck and happy shooting.
William

[R1]

Thinking about this again:  When you cock the rifle, is it smooth or not?  My understanding about coil springs is that when compressed, they rotate a small amount.  If there is a burr on the end of the spring, that may be causing a bind when the spring is unsprung as the ends of the spring will rotate. 

If the spring is getting caught in rotation, that will give you a torque recoil, noisy and harsh, and may be why the scope is rotating.  IF it were mine, I would check with the Mfgr. and see  about a return and replacement.  If you are not worried about warranty, I would take it apart and polish the spring ends and check for a smooth bearing surface for the spring.

I probably don't know what I am talking about, but seems reasonable.

Good luck!

[OsiViper]

I've had more than 1 set of poorly machined rings. Bought a 30mm set a while back and scope was loose, no matter what i did it even tightening it all the way down the scope was still pretty loose. Measured the gap with it tightened all the way down with calipers and it was 34mm at the largest point and 32 at the smallest.

[Sfttailrdr46]

Thinking about this again:  When you cock the rifle, is it smooth or not?  My understanding about coil springs is that when compressed, they rotate a small amount.  If there is a burr on the end of the spring, that may be causing a bind when the spring is unsprung as the ends of the spring will rotate. 

If the spring is getting caught in rotation, that will give you a torque recoil, noisy and harsh, and may be why the scope is rotating.  IF it were mine, I would check with the Mfgr. and see  about a return and replacement.  If you are not worried about warranty, I would take it apart and polish the spring ends and check for a smooth bearing surface for the spring.

I probably don't know what I am talking about, but seems reasonable.

Good luck!

Actually the torquing is a real issue and will cause the problem being experienced. A burr on the end of the spring is easily corrected and since the rifle action is not sealed and locked a quick disassembly should not void the warranty if the clean and polish does not mar the fit and finish of the external parts.