Rem M700 300 BLK to 308 conversion

You’d either need a new bolt or have yours opened up by a gunsmith and sako or M16 style extractor installed and then you’d need to have everything headspaced and for the $$ it would be crazy not to spin up an aftermarket barrel at that point.

Basically you’d be money ahead to sell your 300BLK and then go out and purchase a nice 308 rifle of your choosing, ideally not another Remington.
 
You’d either need a new bolt or have yours opened up by a gunsmith and sako or M16 style extractor installed and then you’d need to have everything headspaced and for the $$ it would be crazy not to spin up an aftermarket barrel at that point.

Basically you’d be money ahead to sell your 300BLK and then go out and purchase a nice 308 rifle of your choosing, ideally not another Remington.
Thank you very much for the info, really appreciate it