Winchester M70 Action

I have a custom heavy barrel M70, caliber 243 that was built on one of the controlled round push feed actions. This is the one where they machined away the bottom of the bolt face of a push feed action to make it a control round feed. When I bought the gun off an auction site this was not in the description because the seller did not know the difference and refused to take back the gun. My problem is that the gun has broken three extractors with loads that are below any minimum load in any manual. I would like to replace the bolt with a regular push feed bolt. I realize the headspace would probably need to be corrected. Does anyone know if this can be done?