Need help with Bering PU 90 repro scope mounting

[smlemon]

It's a nice scope and mount but the maker doesn't bother to say what the drill and tap sizes are for the supplied screws. Looked at too many UTube videos and chased all over the web...no joy.
Would appreciate help. Thanks.

Information

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[Drift]

Hello Smlemon,

I don't know the original specs for the PU or the Bering PU mount. Though a few things I can possibly suggest:

1. Take it to a local machine shop and get them to gauge/measure it. The ones here in Canada usually have both Metric and US (plus other) gauges. I'm not sure what standard (if any) the original guns were built to (on many older pieces of machinery threads were not standardized, some industries and countries changed earlier or later than others).

2. Someone more knowledgeable than me here can help you (that should leave a lot of help available.

3. I'm getting an Accumounts pu mount in the mail soon with the correct tap for the screws it is coming with. I don't know if they match the Bering PU mount, but I'm happy to let you know what the Accumounts screws are.

Good luck and please post what you find out in the end.

Peace,

J

[Peter Laidler]

Does it a), come with the scope or b), do you have one to fit? This is an important question. If a) then take this scope off and collimate it so that the optical axis is exactly true to the mechanical axis of the telescope*. If the answer is b), then get a telescope before you go any further and collimate it as at a).

To do the job properly, we need to know those answers before you can proceed. You could just screw it on of course - but I'll tell you how to do it correctly

* Will tell you how to do this if you ain't familiar with it

[smlemon]

The scope is not the issue. I am well versed in drilling and tapping receivers. What I do need to know is the drill and tap size to match the screws incuded in the kit.
Thanks

[Sentryduty]

In the case that this item is a reproduction the threads on these screws could be a total crap shoot depending on country of origin. For example, I have encountered Chinese produced items with standard heads cut with metric threads below the shank. I recommend buying a set of thread pitch gauges to verify for certain what you have, they should be quite cheap and will be an asset to further tap and die work.

[Peter Laidler]

Exactly as Sentryduty says............ Just go and get some high tensile screws locally that the hardware dealer KNOWS the size of. Get tap to suit - unless you have one. End of problem!