have you put your hand on the screw yet? if not, i got this advice for you.
i always got strip or broken allen, screw, nut... etc, in my car, and also my shotgun once.
wat i did, i asked my friend, who own a workshop doing welding and soldering.
he infact, use a small rod, according to him, bronze rod is recommended (its harder interms of flexis), solder the screw together with the bronze rod, let it cool down. and u can strip the screw by turning the bronze rod.
he did it for my shotgun sxs little tiny strip screw in the firing pin area. he did it for me on my car cyclinder head cover nut.
can give a try, but u need someone is good in soldering or welding.