I carry a S&W 410, which is almost the same gun, only with a Glock-ish style slide instead of a more rounded slide.
The 411/410 and also the 4006 all use the same magazine. So maybe if you find a source for 4006/410 mags you will have more luck. One difference you might run into is that my 410 came with 10 rd. mags and the 411 came with 11 rd. mags, but they both worked in my 410.
I once shot an IPSC match with very high round counts on all the stages, the Croc Dundee Banzai Ballistic. I had my 4 mags which usually was sufficient on "normal" stages, but I borrowed 2 411 mags from a buddy of mine and then a pair of 4006 mags from another guy shooting the match. All worked fine.