1 Attachment(s)
Different Sizes of MRDS Windows
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:
Attachment 117111
(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.
Experience and context matter.
I’ll begin with a caveat: I don’t have experience with all the sights listed in the OP. That said, I think a larger window is better or more forgiving of misalignment or an index that’s off. Anecdotally, I saw this when I shot some rounds with a Holosun Comp (BIG window) a few weeks ago that was on a colleague’s pistol. It was “easier” to find the dot/see the streak for me. Typically, I’m shooting an ACRO on an MOS Glock for reference. The ACRO frame is thicker, and there is the visual clutter of the battery cap.
But, for context, I would still go with the ACRO or other enclosed optic for duty/self defense. First, I like the enclosed emitter for durability. Second, I’ve had the experience of a partially blocked window with an open single lens. That affected my preference. For me then, the smaller closed emitter is my choice. I just realize that I will have to work a little harder and be disciplined about practicing my index dry.
For competition, no argument- the larger window would be the way to go. There may be some visual advantage to a circular window, e.g., an SRO or the C&H Comp. That big Holosun did impress me.
None of this matters much unless one works with the sight. I’m sure there are folks who can do acceptable work with an RMR. They would have to work harder at it IMHO.