Your M-70 SA should drop right into an SPR cut McMillan or Manners stock. Your M-70 likely has a hinged floorplate, so specify that as SPRs also come with a different bottom inlet DBM/TBM. Either the DBM or TBM should feed the .22-250 just fine if you wanted to change magazine type. If not, just specify hinged floorplate, McMillan has that pattern, too.