365x Romeo Zero Sight plate

Normal? No, probably not. You can contact Sig and see what they say. But, the R0 is one of the lowest price point optics on the market, so some economies in production were taken. Perhaps in your case, that particular optic has a higher than average current draw. Or the original battery was poor quality and didn't last very long? I’ve had good luck with Duracells. I replace them on my birthday.

You are correct, your pistol model number doesn’t come with a rear sight plate.

The battery that came with the optic likely sat on a container ship, then in various warehouses for months.

Usually a good idea to start with a fresh one, but I have no idea how to know how 'fresh' they are at the store.

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I'd give right arm to be ambidextrous

Thanks for your replies. Reading the info from Romeo Zero I found this... "Highly efficient point source LED emitter, for up to 10 years of runtime from a common CR1632 coin cell battery ". I am not sure if they are saying 10 years is the life of the laser or the battery. I am pretty sure they do not mean 10 years of accumulated use. I think it means 10 years of average use. That is a huge exaggeration IMHO.

The battery definelty should not be dead but those are not great so i'm not totally surprised. you do not need a mounting plate though.