This:
https://gallowayprecision.com/...for-sig-p239-pistols

Fits and functions perfectly on the P210.
Gives 9-round plus one capacity and doesnt look bad at all.
Just thought you should know.

So you are saying a P239 mag with this baseplate will function in a P210A Standard?

I think he's saying you can add this base plate to a P210A mag

239 plus one base attached to the 210 magazine.

Looks like this:

Kinda ruins the lines of a gorgeous gun but it’s good to have options. The 210 mags can be tough to find.

I am pretty sure he is saying that the +1 extension originally designed for P239 magazines can be used on P210 mags—not that P239 mags will work in P210 pistols.

Bit of a shame that the P239 mags won't work in the P210. That additional use might encourage someone on the aftermarket to start building p239 magazines.

Cool!

Can't say that I would have tried swapping base plates like that.

Good to know.

A nice P210 either way. Welcome to the forum.

Looks like the p225 magazine is the closest one. The followers are different and the latch slot is lower. But that mag body is close.
Next closest is the Smith and Wesson 3904 and even the walther p-38.

As scarce as parts and pieces are for the 210s in general, always glad to see any options there might be.