Completely depends. Are you talking strictly home defense? Like zero the gun then have it under the bed on standby for most of it's life? Or do you plan on training/competing with the thing?
If you have the choice of an optic for an HD gun pick up an aimpoint. No need for a 1-6 unless you are using it in a different role. If we are talking just a bedside gun on a budget I'd skip the optic all together, put a surefire light on an MOE forend and call it a day.
Rick
For a HD rifle have there been plans for a light? I would go the the rifle that you can walk away with a full system- light, optic, sling, and enough money to validate the data on your chosen Defensive round (figure 500-1000 rounds).
Why the SVS 1-6 for the optic?
Got ya - vision is definitely something to consider that would rule out irons. Is there a particular reason you have you are set on the US Optics glass?
I considered a Vortex Razor but the 34 mm tube on the SVS tilted the scale.
So the 34 or 35mm optic tubes when properly used have an advantage in terms of eye box- it’s the physics of optics that dictate that, I was asking to see if there were any other reasons in the choice.
HK upper, zero thinking about maintenance.
So you are right: exit pupil is determined by magnification range and objective diameter. The tube diameter does help light transmission and looser tolerance on head placement.
The latter I got from the Nightforce rep who said the NX8 has a smaller eyebox than ATCR because the tube diameter allowes for larger lenses which helps with larger exit pupil, light transmission, and more front to back tolerance in head positioning.