Variables Scopes --- Do they all gum up after a while?

[southfork]

I went to a couple of LGSs today and checked out some used bolt action hunting rifles (30-06 and 7MM Mag) with variable scopes. I was very surprised to find that half of them were hard to turn from the 3X to the 9X, and back again. It took a firm grip on the optic and some muscle to vary the magnification. What causes this and what is the remedy? If it were an easy fix to un-gum them, I would think that the LGS staff would have done it before putting their price tag on these used hunting rifles. Not so?

[MrMurphy]

Most people use cheap scopes, and never maintain them.

A good quality scope might do it but it is going to take some time.

Not a big scoped rifle user (i have a total of one) but I've shot my fair share of very high end optics while on the job (as in, scopes costing $1-7,000, not counting the mounts) and from the guys who were the pros using them, it takes a lot more to screw one up even after a dip in mud or a sandstorm than say your average $150 rifle scope I see on most deer rifles..

[Mescalero]

southfork,
That is only one of the things that they do.
My rants about variables are long and now ( to me ) tedius.

[AJMD429]

I've got several 5-20x and 10-40x Tasco and Weaver scopes that are just fine some 20-30 years now.

[6pt-sika]

I'm an advocate of Leupold products and have been for well on 35 years .

With these I've not had an issue you mention , but if I had I wouldn't have worried their service department is second to none or atleast that's been my experience .

[jnyork]

Older scopes that haven't been turned in years often do this, it has to do with a nylon (or plastic) bushing that the adjustment ring rides on, it gets hardened with time if not "exercised". I have had a couple of older scopes with adjustable objectives that were pretty much frozen up due to this problem.

[92&94]

I've fixed a few of the 1960's Weaver variables. A variety of problems come up with those, depending on the design. Other brands, I don't know, have to take a look inside and figure out what's causing the problem.

Personally, I don't much care for variables either. If one wants a cheap scope, it's best to stick with a fixed power if you can.

[Pete44ru]

.

The stiff power ring issue isn't confined to inexpensive scopes - I bought a rifle in the 1970's which had a comparatively expensive (for the day) Denver-made Redfield 1-4x that had that problem.

I sent the scope to Redfield, who fixed & returned it shortly.

.

[Malamute]

I havent had a problem with it, including with one or two that werent used for several years. I have one Redfield "Frontier", which I think was an ecnomy grade scope. I got it in the 70's. I'm still using it on different rifles as needed. As a 2-7x, its a great general purpose scope and one of my favorites, even though not the same grade as the Leupolds I really like.

Have one fixed power Weaver that the focus is locked up on. It turned a little when I first bought it used, then wouldnt budge. I tried different oils, no go. Some black gunk came out when I first had it and used one of the oils, but shortley thereafter the scope wont move,...and its nowhere near focussed for me.

[92&94]

Have one fixed power Weaver that the focus is locked up on. It turned a little when I first bought it used, then wouldnt budge. I tried different oils, no go. Some black gunk came out when I first had it and used one of the oils, but shortley thereafter the scope wont move,...and its nowhere near focussed for me.

Where is the eyepiece in it's range? Near the front, back, or middle?

[92&94]

.

The stiff power ring issue isn't confined to inexpensive scopes - I bought a rifle in the 1970's which had a comparatively expensive (for the day) Denver-made Redfield 1-4x that had that problem.

I sent the scope to Redfield, who fixed & returned it shortly.

.

That could well be the case Pete... no one lets me rip their Redfields apart though

I'll tell you though, I've fixed far fewer older Weavers than the last ones before Weaver closed up. The first generation of o-rings they used in the sealed scopes didn't last and there were all sorts of problems from that. I've only ever worked on less than a half dozen of the older ones, mostly those the balsam failed in the lenses and they needed re-gluing.

[Malamute]

Have one fixed power Weaver that the focus is locked up on. It turned a little when I first bought it used, then wouldnt budge. I tried different oils, no go. Some black gunk came out when I first had it and used one of the oils, but shortley thereafter the scope wont move,...and its nowhere near focussed for me.

Where is the eyepiece in it's range? Near the front, back, or middle?

It looks like its towards the rear (out) end of its adjustment range. The lock ring turns OK, the eyepiece doesnt move.

The image is in focus at about 20 feet, but the crosshair is out of focus, and anything past about 20 feet is out of focus.

Just got it out, its a K4-1 fixed 4x.

I think I tried break free, then kroil, then I think acetone to try to get whatevers sticking it to release. No go. Have thought of setting it in rings so I could get better control of one part, but havent. I'm afraid to put much force on it.

Have another Weaver, a fixed 3x that one of the lenses came loose and looks like it may have hurt the lense coating when it contacted the nearest lense inside the scope. Think that was the rear lense.

[92&94]

Have one fixed power Weaver that the focus is locked up on. It turned a little when I first bought it used, then wouldnt budge. I tried different oils, no go. Some black gunk came out when I first had it and used one of the oils, but shortley thereafter the scope wont move,...and its nowhere near focussed for me.

Where is the eyepiece in it's range? Near the front, back, or middle?

It looks like its towards the rear (out) end of its adjustment range. The lock ring turns OK, the eyepiece doesnt move.

The image is in focus at about 20 feet, but the crosshair is out of focus, and anything past about 20 feet is out of focus.

Just got it out, its a K4-1 fixed 4x.

I think I tried break free, then kroil, then I think acetone to try to get whatevers sticking it to release. No go. Have thought of setting it in rings so I could get better control of one part, but havent. I'm afraid to put much force on it.

Have another Weaver, a fixed 3x that one of the lenses came loose and looks like it may have hurt the lense coating when it contacted the nearest lense inside the scope. Think that was the rear lense.

Once they started filling them with nitrogen or something like that there was a snap ring at the end of the tube to keep you from pulling the eyepiece off and losing the gas charge. I've come across one or two backed all the way into that ring and stuck good. One thing that works now and then is that grippy foam stuff you can buy at Walmart for lining dish shelves or whatever the girls do with it. In one case it took vise grips on the scope tube, but that was a parts scope anyhow so I wasn't worried about roughing it up.

If the bezel for the rear lens has wrench slots, then it may just be rusted on - they stopped using slotted bezels about when they started putting o-rings everywhere and filling them with gas. I've never seen one rusted tight, that would be a bit surprising though not impossible.

[AJMD429]

I'm not a big variable-scope fan, but if I want to stay under $500 or so and want 20x (or even moreso if you want 40x), you about have to get a variable. I've had ZERO problems with the 10-40x on a couple 223's and a 6mm Rem, and the 5-20x on a couple 308's, as far as clarity in 'reasonable' light, and repeatability of adjustments. So far, no 'freezing', but I do use the adjustable objective a lot, and turn the magnification down to 5 or 10x if I'm going to shoot offhand.

[Malamute]

Have one fixed power Weaver that the focus is locked up on. It turned a little when I first bought it used, then wouldnt budge. I tried different oils, no go. Some black gunk came out when I first had it and used one of the oils, but shortley thereafter the scope wont move,...and its nowhere near focussed for me.

Where is the eyepiece in it's range? Near the front, back, or middle?

It looks like its towards the rear (out) end of its adjustment range. The lock ring turns OK, the eyepiece doesnt move.

The image is in focus at about 20 feet, but the crosshair is out of focus, and anything past about 20 feet is out of focus.

Just got it out, its a K4-1 fixed 4x.

I think I tried break free, then kroil, then I think acetone to try to get whatevers sticking it to release. No go. Have thought of setting it in rings so I could get better control of one part, but havent. I'm afraid to put much force on it.

Have another Weaver, a fixed 3x that one of the lenses came loose and looks like it may have hurt the lense coating when it contacted the nearest lense inside the scope. Think that was the rear lense.

Once they started filling them with nitrogen or something like that there was a snap ring at the end of the tube to keep you from pulling the eyepiece off and losing the gas charge. I've come across one or two backed all the way into that ring and stuck good. One thing that works now and then is that grippy foam stuff you can buy at Walmart for lining dish shelves or whatever the girls do with it. In one case it took vise grips on the scope tube, but that was a parts scope anyhow so I wasn't worried about roughing it up.

If the bezel for the rear lens has wrench slots, then it may just be rusted on - they stopped using slotted bezels about when they started putting o-rings everywhere and filling them with gas. I've never seen one rusted tight, that would be a bit surprising though not impossible.

Interesting information.

It moved somewhat when I got it like I said, but I didnt do anything wild and crazy with it. It seemed more like it had some sort of glue or gunk that set up, since it moved (with effort) then stuck hard and fast and hasnt moved since. Doesnt look like rust, the oil and kroil should have helped that, but I guess it could be possible. The sticky black gunk that came out at first seemed weird.

I'll try to turn it on and see if it moves. I dont think it ever moved inwards much when it did move.

Thanks for your thoughts on it.

[92&94]

The black gunk could well be the remnants of the o-ring, it's right inside that snap ring if the scope is one that has those. I've yet to see it harden up, seems like they just get more gummy.

Of course, all this info is limited to the 100 or so broken ones I've taken apart (a friend of mine collects them), but if any of it is useful you're welcome to it

[Old Savage]

Mine haven't, Leupolds. No problems.

[Mescalero]

Malumute mount it in the rifle, turn the ocular ( eyepiece ) toward the right ( clockwise ) you can apply as much force as a person with strong hands can.
It sounds to me that it has become jammed against the ocular lock ring.

[Malamute]

The lock ring is free. It runs freely the length of the threads. Theres about the width of the lock ring of threads between the ring when all the way forward, and the front of the occular eyepiece.

The black gunk seemed like a sticky liquid, but I guess could be a dissolved o ring. After that first time it appeared and I wiped it off (was about the consistancy of thick oil IIRC, it got on my hands as I tried to turn the eyepiece with the lock ring run forward), I havent seen any of it, and the eyepiece hasnt moved since. It felt gummy to move when it did move. I dont think I ran it back hard and jammed it, but at this point I cant rule it out. It didnt seem to make sense how it seized up, as I was able to move it somewhat when I first got it (gun show buy), so figured it would adjust OK.

I need to find some rings, I can mount it on a Ruger 77 to try to turn it.

[Mescalero]

There is an internal lock ring that is not visible in the assembled state.

[Paladin]

I'm an advocate of Leupold products and have been for well on 35 years .

With these I've not had an issue you mention , but if I had I wouldn't have worried their service department is second to none or atleast that's been my experience .

+1

[6pt-sika]

I might add over the last two or three years I've thrashed a couple decent old Weaver variables and a couple nice old Redfield Traditional variables .

Might add that I have a pair of Redfield Traditional 6-18xAO scopes that are still doing fine and yes I bought them both used .

Should also say the variable Weavers and Redfields I thrashed were on a few of my 444's when I was working up loads . And I was working up some fairly stout cast bullet loads . It was a shame to as one of the Weavers was a 1.5-4.5 and it looked very nice on my circa 1966 Retro 444P .

[southfork]

So, is it OK to put penetrating oil on the threads of a gummed up variable scope, then?
Or, does that penetrating oil just get inside the scope and cause more problems? If its a hardened plastic O-ring causing the stiffness, then the penetrating oil might not help anyway.

[Bronco]

What brand are they ?
If leupold or some other good brand , call factory to see what $$ it would cost to send in for repair. With leupold repairs are free, some other also.

If it works out, you might get the scope from the lgs for a song and a dance because they are froze up.

John

[WinM71]

I've got a 6-18x Redfield that I got in the mid 1960s, and I've used it a lot. Never the slightest problem.