swd
Silver $$ Contributor
Yes they're 18 TPI but have a essentially a flat breach w small cone to fit the outside of the lugs on the bolt. Why the just didn't spec out a straight flat beach I don't know. They won't fit a cone breech Borden or Bat etc..I believe they are the same pitch as Borden and several others, i.e. 1 1/16 x 18 TPI Threading for barrel tenon versus Remage 1 1/16x16.