HELP,my scope moved!

[Grawer]

Grawer, your basic problem is using rings on a CZ that's not made for a CZ. Many manufacturers (Leupold, Warne, Talley to name a few, I use Warne's) make rings specifically for CZ/BRNO rifles. He rear ring should have a stud that fits in the cutout on the left-hand side of the rear action ring.

It is the correct rings (leupold ones), in pics 2 and 3 you can see the stud. The guy at the gunshop did not know how to mount them properly, and moved the rear ring over the action as seen in pic 1 to overcome the stud being in his way.

[DS]

Imo the biggest culprit for scopes coming loose is the ring bases and/or the ring halves not being evenly torqued down to manufacturer specs.

[Pirate]

It is the correct rings (leupold ones), in pics 2 and 3 you can see the stud. The guy at the gunshop did not know how to mount them properly, and moved the rear ring over the action as seen in pic 1 to overcome the stud being in his way.

Ah.... eish...

[tobie]

It is the correct rings (leupold ones), in pics 2 and 3 you can see the stud. The guy at the gunshop did not know how to mount them properly, and moved the rear ring over the action as seen in pic 1 to overcome the stud being in his way.

I think you need to be a special kind of "Deur die kak" to manage this. If something does not seem to look or fit right, why don't you just consult the internet?

[Dick]

Hi Slipie,

The only decent advice in this thread is the recommendation by tcbc to lap the rings. I fitted a lot of scopes in my short gunsmithing career, and discovered some basic facts of life that are not admitted by ring manufacturers and seem to be disbelieved by most rifle owners. I wrote a whole book about it, but sadly it didn't sell more than a handful of copies. But let me spell it out for you as briefly as I can. Rifles and scope bases and rings are, like all engineered items, manufactured to tolerances ie they are not zero error precise. I never found a pair of rings that were perfectly parallel to each other. They were ALL out to some extent - not parallel, leaning sideways, leaning backwards or forwards. It's not visually apparent but all it needs is a few microns to do the damage. If a ring is leaning forwards it will grip the scope by it's edge, and that point contact won't stop the scope from slipping no matter how much you tighten the top cap. Furthermore, it is not uncommon for the powerful point load to press a groove in the scope tube. In the worst cases it will scrape the finish of the scope when the scope slips, and there's a photo in my book showing just that. Of course, it's only the worst cases that actually result in the sort of consequences that happened to you, but that doesn't mean that the others are OK. After I discovered this phenomenon I lapped all the rings I fitted. When you start lapping a pair of rings it clearly shows that they are out, and in which way they are out. When you drop a scope into a pair of lapped rings you can feel the complete all round contact between rings and scope. I've said all this so often and ended up in arguments with guys who don't believe it that it's tiring. But if you'll e mail me at boothroyd@polka.co.za I'll send you some photos which I guarantee will get your attention. You don't need to pay a king's ransom for a lapping tool - pay a local machine shop to make one for you. It won't be dirt cheap but you have it for life. Alternatively sell it after you've used it for a lower price.

[Dick]

I should have added a few other things. There has been a lot of discussion of this in the past and I came under a good bit of attack for my views. Many years ago I got the admission from a ring manufacturer that their rings, at that time, had delrin inserts precisely because rings were never straight. But I no longer have that so I can't prove it. All the padding, tape, glue or whatever some guys have told us they use to make their rings hold their scopes are no substitute for the precise fit that can only be accomplished by lapping. More recently somebody contacted Warne who told him that their rings don't need lapping. A regular contributor to Gunsite whom I won't name because I haven't obtained his permission, fitted several sets of rings including two sets of Warne, both of which he said needed lapping, and one was the furthest out and needed the most lapping of all the rings he fitted. Somebody in the US told us that, as a dealer employee, he fitted as many as twenty scopes a day. My experience was that proper installation, including lapping, followed by bore sighting in the shop, took at least two hours and the more difficult ones as much as four hours. Some of the scopes with very big objectives couldn't be optically bore sighted because the scope was so much higher than the bore scope that it couldn't see through it. Those had to be bore sighted to a target on the shop wall. Another problem of very big objectives was that they needed high rings, and in some cases the scope was so far above the rifle that it prevented a proper cheek weld on the comb. Sako, CZ, Tikka and Ruger rifles have machined dovetails on their receivers, intended to accept rings that fit directly ie no bases needed. But direct mounted rings permit no lateral or rotational adjustment. Other types have their own problems eg the "standard" Redfield type also copied by Leupold and others, require the front ring to be inserted into a slot in the base and rotated 90 degrees to lock. They can be so stiff that it puts unacceptable stress on the scope if the scope is used as a tommy bar. I made up my own tommy bar to avoid using the scope. But even then, the method of laterally adjusting the scope with the rear ring also puts sideways stress on the scope, and I have no doubt that that's why Redfield introduced it's double dovetail bases in which both front and rear bases install in exactly the same way. But those have their own problems and need two separate tommy bars to line them up. Thor "stud" type rings are the easiest to install because they have 360 degree rotational adjustment and a lot of lateral adjustment. Their downside, if it is a downside, is that they are taller than most other rings ie a low Thor is about the same as a medium of most other makes, because the stem must be tall enough to accept the pair of grub screws. Its a fact that most dealers even gunsmiths fit scopes badly, and rifle owners can do a better job themselves. But it's not quite as simple as buying any set of bases and rings and slapping them on. It needs a bit more knowledge of what to buy and why. And knowing how to install them properly. But it's not rocket science, just needs a bit of application. I never used a torque wrench - it's just another expensive fad. But you do need to develop the feel for what's enough torque before you break a screw. The upside of that, of course, is that lapped rings are in complete contact with scope tube all round, and don't need the hell tightened out of them to hold the scope securely. I support the use of Loctite on the screws, but there are different grades, be sure to use the one that will let go with mild heat if ever you need to take off the rings. I've forgotten which that is, but be aware that there's a grade that will lock your screws permanently.

The conventional way of lapping is to use a perfectly straight and concentric rod exactly one inch diameter (or 26mm or 30mm) coated with lapping compound. Although a little projecting handle like you get with those fancy kits is nice to have it's not necessary - a good grip with fingers is all you need. My rod is 250mm long. 300mm is better but anywhere between those is OK. Any half decent machine shop can make one for you. But there's a practical alternative. Free cutting bar is usually bright drawn, usually very straight and concentric within close limits, and available one inch diameter. I rolled a few 300mm long bars on a piece of plate glass to see whether any curvature could be seen. I saw none and couldn't get a piece of kitchen foil to pass between the bars and the glass. That amounts to perfect straightness within a few microns. Roundness was near perfect and consistency from end to end within a few microns. That's plenty good enough for lapping. Just be aware that lapping will take something off the lapping rod, so it's a good idea to measure diameter with a micrometer before each job. I did it a bit differently. I found that a bar machined to 24.20mm diameter with a single thickness of 220 grit paper did a good first pass. I say "first pass" because I found it useful for cutting down to depth, before making a second pass with both a piece of copy paper and a piece of 320 grit wrapped around it. That had the effect of bringing the width of cut to size and finishing the bottom. I found that it was easier and got a good result. And because lapping compound isn't used the rod never wears out. Oh, before I forget, I'm not at all reluctant to post some pics, but I've never learned how. And don't forget the cold blue after lapping.

[FNBROWNING]

Dick's comments apply doubly on Mauser 98 rifles. In an ideal world a single piece mount or rail system is the way to go.

[janfred]

Nothing beats a good lapping job and it is not difficult to do. The aim is to get as cli6se to 100% contact as possible. Just remember, the job is only good enough for the rifle the rings are currently on. If you use the rings on a different rifle, you will have to re-lap the rings .

[Dick]

Nothing beats a good lapping job and it is not difficult to do. The aim is to get as cli6se to 100% contact as possible. Just remember, the job is only good enough for the rifle the rings are currently on. If you use the rings on a different rifle, you will have to re-lap the rings .

Yes, exactly right.

[Slipie]

Thanks guys, really appreciate all the knowledge that you are willing to share.
For now, there were two screws that was loose, sounds like lapping the rings is the way forward, will jump on that somewhere in the next week or so.