Nesom extension tube

[dezzick3]

Afternoon all,

I have taken the advice of a few of you on this forum and will shortly be ordering an extension tube from Barry Nesom. I am a 6 foot 2 male who has my handstop pretty much at the front end of the stock (Precise) and the butt all the way out, I assume a 12 inch one is the best length to go for?!

For anyone who has a Nesom tube would you mind posting a few photos of it? I'm curious to see what my imminent purchase will look like!

Many thanks

[Tim S]

For Prone shooting? If yes, then go for 12in. Barry cuts a full-length dovetail on the tube, so you can position the foresight at any point along the tube, if you find a specific position works best for you.

The only caveat is that you'll need a much bigger foresight aperture. If you have an iris aperture, not all will go large enough, especially with an eagle eye lens.

[dezzick3]

Thanks Tim.

Yeah I'm aware of the foresight thing, I'm buying an M22 foresight tunnel to upgrade from my M18, mainly because I want one. I currently use a 3.7 insert and apparently one needs 0.1 extra for every inch of extension tube so would need a 4.9. However I might just buy an adjustable iris, I'm not sure that I would have the foresight all the way down the tube and I'm not keen on buying several High End elements! I'm also very lazy...

Oh and one more thing will I need rear sight raisers or are Barry's tubes the same diameter as the barrel?

[Tim S]

Barrey's tubes are approx. 25mm diameter, so rougly the same as a 1913 at the muzzle. But the M22 foresight will sit higher than the standard Anschutz M18. Most rearsights will have enough elevation to just click up, but a 4mm raiser under the rear should keep it centred.

Foresight size isn't quite so simple. I think a better way to keep the proportion between sight radius and barrel length the same. I use a 4.1mm on a standard barrel, but went to a 5.7mm aperture with a 12in tube. There was a handy excel calculator on the Stirton.com website, but any calculator will do the same job.

[dezzick3]

Hi Tim,

Thanks for your reply, I am aware of the spreadsheet on Stirton but unfortunately I am still not verified for the website!

I am appalling at maths, but you have got 1.6 extra for the 12 inch tube, is there a specific sum that can be done or should 1.6 be fine?

[GaryD]

I am using a Nesom 12 inch tubes with a 22mm Nesom sight on the front of it.

I bought a few cheaper plastic foresight elements to experiment with before buying a 5.2 Centra High End, I also have a 4mm riser on the Anschutz Canting rear sight.

The reason that I fitted a riser block was to center the sights as I use a Lenshood II on it and it was very close to the Anschutz anti glare tube, but depending on which foresight you use you might get away with it.

[dezzick3]

Hi Gary,

Thanks for your advice, I can't find any larger plastic elements online but I might ask my local shop if they've got any in demo stock, before buying the High End.

I'll be using the Centra Score tunnel, might get a 4mm raiser once I've put it on the tube as I imagine it might be a bit higher.

[Tim S]

It's not just the difference in tube and barrel diameters; lengthening the sightbase reduces the angle between the rearsight and foresight. The foresight is always a little lower than the rearsight to account for the bullet trajectory, so with a tube the rearsight has to go up, whether by clicking or a raiser.

[dezzick3]

Tim,

Ah, I hadn't thought of that! In that case, I'll buy a raiser.

[Andre]

The Anschutz 20 click sight has a ton of vertical adjustment, Mine is run like 30 clicks from the top. (Tube is a bigger diameter then the barrel)

Not sure what 22mm front sight you bought, but if it's the Centra Score series the tube, riser, and base are different pieces screwed together. You can take out the middle riser and file it down if your rear sight runs out of adjustment.

[Tim S]

Having run out of elevation between 50m and 100 yards once before, which takes about 80-90 clicks on a 20 click sight, I now don't like having the rearsight anywhere near the top of its range.