Action Threads


Distinguished Member
Makers regularly (over a period of years) change the thread OD and pitch.

One has only to look at Sako and Tikka to be easily confused….

Most Custom actions are 1.0625" x 18Tpi or 16 Tpi (though some have larger OD)

Rems are usually (unless they've been blueprinted) 1.0625" x 16Tpi

Tikka and Sako could range from .900" x 16 Tpi to 1.00" x 16 Tpi

Though this isn't prescriptive by any means,,,,,and I ALWAYS check the take off AND and action diameters before I machine a new barrel to fit.


Well-Known Member
Barrels and Actions by Harold Hoffman has a very comprehensive list including a lot of the old stuff, like Enfields, Mausers, Springfields and Rolling blocks.
It has detailed specs on thread froms, both 55 and 60 degree forms and square threads as found on the above, as well as lists of bore and groove diametres for most calibres.