I had asked a question on window size over in the Romeo X thread, asking for confirmation that the window size of the Romeo X Pro and Romeo X Compact were the same - they are.
It turns out I had been working updating all 12 of the EPS and EPS Carry MRDS Quick Reference Cards to Revision 12, which includes (where I know the data) the physical window size. So I had this on my mind. I got kinda bored this weekend so I did some research and dug out what I believe are the optic window sizes for several popular dots, and put them into a graphical representation, large to small:
(The numbers are width x height, inches. For Holosun, I got the numbers off their web site. For the Romeo X, I asked a user on the Gen Pop Sig web site for a measurement. The Trijicon values are measured using a steel ruler on a printout pdf that Trjicon supplies online. Close enough for government work, maybe).
Some thoughts/questions.
Does window size even matter? Consider an optical spherical cow: Ideally, the optic reticle would appear in free space, projected as a hologram. At present, the technology is such that the reticle is refracted off a prism (normally glass) over the emitter, with infinite focus. The glass is not sufficiently robust enough to stand on it's own, so we have to have a shroud (typically 7075 T1 aluminum) which encloses and offers some protection against impact.
Does a large window offer an advantage over a smaller window, if one's index is sufficiently developed? Perhaps for novice MRDS users, working to acquire the dot on presentation consistently? But does a M/GM shooter really worry about window size?
Anyway, food for thought.