Extension tube length question

[WingsFan]

I got my new 21 inch Lilja barrel last week, and it needs an extension. With my limited experience I've never shot anything longer than a 26 inch barrel yet. With a barrel plus extension length what are the practical differences in a 30 vs a 33 inch length or something in between? For sight radius it's 4.5 inches between the rear iris and the barrel.

Thanks

[Tim S]

Practically there won't be a huge difference between a 26in barrel, and a 21in barrel +6or 8in tube. Add a 12in tube, and it's more noticeable.

You would need a larger foresight aperture if the sight radius is longer than before. I used a 4.1mm on a 27in Anschutz barrel; with a 6in tube this went up to 4.8mm, and to 5.6mm with a 12in tube. I worked out the sight base-aperture ratio on a pocket calculator and applied it to the new longer sight base.

[WingsFan]

I was thinking of a minimum of 30 inches, but have the possibility of going to 33 for no additional cost on the extension tube, and could go up to 36 for an extra $10. It's also got me considering a 22mm front globe as well.

Thanks

[proneshooter]

At some point windage and weight comes into play.

[WingsFan]

I get windage, but not weight. Most extension tubes are carbon fiber these days and only weight a few ounces.

[Tim S]

I get windage, but not weight. Most extension tubes are carbon fiber these days and only weight a few ounces.

Some are, but plenty are still aluminium. A 12in alu tube could add 8oz+ with its collar. That weight ahead of the muzzle is not comfortable for some. However, I think it's much less relevant on a 21in barrel, as that's going to be lighter than a full length 26/27in barrel.

A 33in barrel +tube isn't enormous, no different to a standard + 6in.

Do be prepared to clean the tube regularly, ideally after each session. They crud up quickly. A bore snake or wad of tissue on a shotgun rod is effective though.

[40xguy]

imo, a longer sight radius gives more accuracy. fyi, a 10.0 front iris opening seems to be the max I could find for a 22mm front sight.
here is a tuner-extension that is very good: beesafeusa.com

[WingsFan]

Tim, thanks for the cleaning suggestions. I have 12 gauge supplies, I can get a 10 gauge mop if needed.

40xguy, the beestinger tube is the one I have been looking at, but was planning on the tube without the tuner.