Okay, now that I have researched the matter a bit, this is what I understand:
When used specifically, “RMR®” refers to Trijicon’s “Ruggedized Miniature Reflex” sight.
“RDS” means “red dot sight,” and could refer to any (usually small) optical sight with illuminated dot reticle that’s also (usually) red, but could be green (I believe).
Correct so far?

If I am correct, whenever I see RMR, can I assume that the user is referring specifically to the Trijicon sight, and not to any of the myriad other similar sights that could be generically called an RDS?
Or is now “RMR” (no ®) an accepted term for any small optical sight with illuminated red dot reticle? I.e., is RMR now like Kleenex that is a generic term for any tissue paper people use to blow their noses? I.e., is RMR just another way of saying RDS?

These days, RMR is often used as shorthand to refer to any miniature red dot, Trijicon or otherwise. Like AR-10 being used for any .308 AR pattern rifle, not just those specifically produced by Armalite under the AR-10 model name. Or like Kleenex/Xerox/Coke, etc.

RMR as an acronym would be technically correct for non-Trijicon pistol red dots, because it stands for "Ruggedized Miniature Reflex (Sight)", but the fact that it's a specific brand's model name can cause confusion when used to refer to non-RMR RMRS .

RDS is also less precise, because it refers to any red dot sight, including larger rifle optics, unless preceded by some clarifying term like "pistol RDS".

MRDS is a more precise and non-brand-specific acronym that some people use, meaning "Miniature Red Dot Sight".

I was hoping you would reply, RogueJSK, knowing that I would receive a correct and comprehensive answer. Thanks.

quote:

MRDS is a more precise and non-brand-specific acronym that some people use, meaning "Miniature Red Dot Sight".

So, to clarify, an "MGDS" is a "Miniature Green Dot Sight"?

I understand a few people use it interchangeably. I object every time I see that and I think all of us should who actually have some knowledge. Its not like xerox. Copiers all take std. size paper and produce copies, indistinguishable. The mounting situation on these things is a huge abomination and they are not able to be interchanged. There have now been dozens of posts about my "RMR" and issues only to find out its not an actual Trijicon RMR but something else and the solutions are not the same.

quote:

Originally posted by hrcjon:
The mounting situation on these things is a huge abomination ....

I don’t know that we could have expected anything different when optical sights for handguns became a thing to do, but uniformity would have been nice.

A particularly annoying example was vague information that the mounting plates for M17 and early P320 slides were not the same. When I tried to just find out whether that was true and whether a plate advertised as being for “M17/P320” would have worked on the P320 slide of unknown vintage I was considering purchasing, I never was able to get a straight answer—and never have. (I still feel bad about backing out on that purchase, but I wasn’t going to risk getting stuck with a slide I couldn’t use for the purpose.)

And thanks for adding your confirmation about careless use of the term “RMR.” I haven’t followed discussions about handgun optics very closely, but it did seem to me that there has been a lot of mention of so-called RMRs that actually referred to other brands/models. That was what prompted my original question here.

Don't forget PMO that's being thrown around as well. Pistol Mounted Optic

It took me six months after I started seeing it to figure out what LPVO means. We have a serious case of TMA going on these days. Too Many Acronyms.