It should be fine on a limited basis if your recoil spring is fresh, and you change it more frequently. Like every 3K rounds instead of 5K. I too have a 439.

Now, that being said, modern SD hollow points don't need to be +P to expand properly. I do have a bunch of +P 9mm rounds, but I'd use them in a 5906 or my HK USP 9 with its double recoils spring. If you really really feel the need for more power, get a .40 or something in .357 SIG. (or a 10mm)