Tube size has no effect. The "tube" that contains the lenses is not related in size to the tube size. The tube that carries the internal lenses has to be able to move up and down at an angle for you to zero the rifle and dial if needed, hence that is never the size of the OD of the body. Bigger tubes allow more erector travel.

Straight from Swarovski:

https://www.swarovskioptik.com/hunting/blog/RS_tube_size_matters_but_not_much

That said, Schmidt & Bender Polar T96 is the brightest to most eyes last I researched. May be something newer that is better.

Last edited by ChrisAU; 01/30/20 02:09 PM.