David - the Rem 700 bolt handles are soldered on. Quite sturdy and failure is very rare if at all. Would the Army or USMC have had their actions for sniper rifles if they were bad?
You can replace rhe bolt handle but you should make a heat sink that'll screw into the bolt body so you can weld a new one on.
I attended Trinidad after I retired. Prior to that I enrolled in 8 classes at Lassen's NRA summer school and most factory armorer schools. I still take a class now and then and sometimes its at the NMLRA Gunbuilders' workshop at WKU (Bowling Green, KY). Most of the time after graduation I write and have four books since graduation.