100-300 or so
100-500 USD or so
Your westernfield model 765 was made for montgomery wards(westernfield) by the mossberg arms company.The model 765 is the mossberg model 810A.
Mossberg Model 810 bolt action made 1970-1979. According to gun traders guide-also two variances-detachable magazine 70-75, internal magazine w\hinged floorplate 72-up
You can check w/ Mossberg, or with havlinsales at their website- but the bad news is that a complete bolt will cost you about half of the value of the rifle, AND it should be fitted by a gunsmith. Sorry-