I've only shot my new to me P239 once but it looks like it is hitting about 3" to the left at 25ft. Looks like I need to move the front sight over to the left a tad... how do I do this?

(I'm going to shoot it one more time to make sure it was not me that day)

There are many tools to drift adjustable sights, to include using a hammer and (hopefully brass) punch. I much prefer a tool that uses a screw mechanism pusher that’s designed and intended for the specific gun.

But yes, unless the sight is visibly off center, it’s always a good idea to confirm the point of impact problem, and ideally by having another skilled shooter shoot the gun as well. Chasing an iron-sighted handgun zero can be a very frustrating experience.

Three inches at 25 feet isn’t too far and could easily be due to shooting technique. What size groups do you get at that distance? Where and how were you shooting: indoors/outdoors; rested/unsupported? What sort of target were you using?

Something to keep in mind as well is that, again, unless the front sight is clearly off center, it’s usually better to adjust the rear sight on SIG Classic line pistols as there is less possibility of damaging the sight. I have broken more than one front sight even when using a proper sight pusher.

If you do need to adjust your sights, I suggest moving the rear sight rather than the front. The rear sight is stronger and less likely to break. Apply some light oil to the dovetail first and let it seep in.