I'm using the 17 round mags that came with it new?The way that extractor looks, I think you need to verify the capacity of your magazines. They may be 10 rounders.
I purchased a 226 Legion in 357 SIG that came with 10 round magazines. It was no big deal with the trade that I got. I use the 13 round MecGars instead of the 12 round checkmates that SIG uses.