I'm pretty sure that screw (and all the other little f***ers) is 2.5mm...and possibly made of hardened butter, because I stripped one myself.
I'm pretty sure that screw (and all the other little f***ers) is 2.5mm...and possibly made of hardened butter, because I stripped one myself.For stripped hex screws, I usually dremel out a slot for a flat head. But you might want to check to see if your hex wrench is the right scale and size first. I can't remember whether scar screws are metric or imperial but the correct sized wrench might still be able to get the screw out.
If you don't feel comfortable about doing any of that then get a gunsmith (or a mechanic/machinist) to do it for you.