Is an adjustable rear sight iris, like the Merit disc, legal in LA?

Rule 3.1.3 and (a) do not specifically exclude it, BUT, you might find that you end up pushing the proverbial uphill.
It could be construed as being "not within the spirit" of the game. A bit like the eventual exclusion of the 308MX.
That reminds me; I must go and track down the magazine article that shows a catalogued, optioned front sight that contained a glass aperture. How old was the catalogue? From the 1890's. There aint nothing new, but I'd bet that it would be excluded if you fronted up with one.

The merit discs have been used for a long time now in LA. I use a new centra on my rear sight but have not had to pass inspection at the nationals yet as I couldn't make it. Merits have become rare when he stopped making them and the centra for the olympic sports is readily available.

Has Merit started making them again?

I didn't know they were out of production .... I have an old one which I will now guard like Gold!

Montana Vintage Arms and Lee Shaver Gunsmithing have Hadley eye cups for sale. I plan on getting one for my CLA rifle. I have been in very cloudy low light situations a few times this year. I could really use the multiple sized holes to be able to balance light with accuracy.
I hope this accessory is not declared illegal for CLA.

Adjustable aperture is not and will not be ever declared illegal….

If you use the ones with lenses and filters those would.

Merit is actually back in business but limited to the small ones last time I contacted him (earlier this year I believe).

I use a Gehman PH510 in a Redfield sight and have been though multiple National and state techs. You can pass a wire through it, no lens.

legal

I have both the Merit and the Gehman I believe that the Gehman does give a better true circle view when you're looking through it. Problem with the Gehman is its size. I needed to raise everything up so it would clear the hammer on my Rossi 357 and my Win 30-30. Don't know what the cost of the Merit is currently but the Gehman will set you back around $90 with shipping.
ppkny

The merit is $59 through eabco.com. They aren't currently in stock, but do allow it to be backordered.