With my S&W Shield I can convert 40 to 9 by changing the barrel and mag.(can also go 9 to 40 with just a little work).
Would it be possible to do the same with my SD40VE?

No, you need the slide to go from 1 to the other.

My .40 mags. work with the 9mm's, feed's fine.

3

Worse yet, magazines and magazine wells on the Sigma series of pistols (SW/SD) are different widths for .40 and 9mm. You can't put a .40 mag in a 9mm frame, and the 9mm mag is rattling loose in a .40 frame.........unlike the M&P magazines, which are the same width between 9mm and .40. Some people say their mags work, like 3hounds above, some say theirs are jamomatics with 9mm in .40 mags in Sigmas. I tried mine just for grins, and it misfed every magfull or two, way too much for me.

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