How to get a scope to focus at 10 metres.

[Aimstraight]

I looked into this recently. I do not have the search results but fairly sure it was wind the front element out a little, but as you say this might disturb the seal and let the gas escape. There was a thread on here recently by someone asking for companies that can re-charge a scope....because he had tried to alter the front element

Turned out my scope (Hawke HD Sport) did not have an adjustable ring at the front....so I bought a Nikko Sterling 4x40 AO from our site sponsor for a very good price.

I wonder if applying (carefully) more of the heavy grease (normally found in the threads of a scope/binoculars) would help minimise the risk of loss of the gas (presume it is low pressure)?

[zooma]

I looked into this recently. I do not have the search results but fairly sure it was wind the front element out a little, but as you say this might disturb the seal and let the gas escape. There was a thread on here recently by someone asking for companies that can re-charge a scope....because he had tried to alter the front element

Turned out my scope (Hawke HD Sport) did not have an adjustable ring at the front....so I bought a Nikko Sterling 4x40 AO from our site sponsor for a very good price.

I wonder if applying (carefully) more of the heavy grease (normally found in the threads of a scope/binoculars) would help minimise the risk of loss of the gas (presume it is low pressure)?

I will make a suitable device to fit into the two small horizontally opposed slots in the front lens holder and if it will unwind OK I will move the lens forwards a little and see if this works.

Some low tack masking tape should help protect the lens but I will put a concave curve into the device to help keep it away from the lens surface.

Your idea about adding a little grease to the threads sound good too!

[Portzy]

What you are attempting to do is re-paralaxing, not all scopes are suitable for this so it would depend on the make/model. Fabricating a tool to fit into the slots that you see on the lens carrier is one way and if the lens carrier is stiff then a small amount of warmth or heat may ease the situation but you must be prepared to accept that the scope could become trashed if the tool slips or you otherwise force the situation.

Ideally, scopes with a decorative trim ring at the end are the easiest. Remove this with a couple of Mini Boa's, if it comes clean off the lens carrier then just wind the carrier out about 1/4 of a turn then check focus/parallax for your desired range and re-adjust as/if required. When all is good re fit the trim ring without upsetting the carrier, this bit can be tricky!

If the trim ring brings with it the carrier then only turn the whole assembly 1/4 turn and check as above. Once you have focus/parallax you have to lock the trim ring and carrier with tape of the black insulation variety.

Hope that makes sense.

Edit: The nitrogen, if that is what the scope was constructed using, is not under any pressure as such. It is used to purge the internals of air which itself contains moisture, the nitrogen is "dry". Moving the carrier should not allow the nitrogen out in the pressurised gas sense, removing the carrier totally and complete with lens will, simply moving the carrier forwards should not.

[Turnup]

Well said Portzy and I agree with everything you have put.

Small thing to think about for those still concerned about the Nitrogen filling: Does you scope have an adjustable eye bell? (nearly all do). Does your scope have a zoom? Just how good at retaining Nitrogen are those sliding seals after years of movement? Unless you are taking the thing apart do not worry about letting the magical Nitrogen out.

[Aimstraight]

Explanation from Portzy helps.

The link below might too:

https://youtu.be/T97GCZqbZio