new guy with question

[butlersrangers]

You really need to 'lead slug' a rifle bore to know its exact dimensions.
My wild ass guess is that your rifle bore will probably measure something like .3085" to .3095" bore diameter.

IMO - This is rather irrelevant, unless you are having accuracy problems with factory ammo & reloads using standard loading-data,
or intend to shoot cast bullets and will be shopping for molds.

As to Pacific sight threads, you might just take your sight-slide to a hardware store, that has bins of U.S. threaded Allen Screws.
Try Allen Screws until you find a thread match and adequate length. Buy several screws.

The shank of the screw can serve as the basis for making a new sight screw:
Cut-off the Allen Screw 'head', make a screwdriver-slot with a handsaw and files, 'chuck' the shank in a power-drill, spin and file some of the threaded-shank
into a smooth shaft that fits into your base, adjust lengths, and smooth the ends.

By all means, try what you do have, first.

[Hunza]

Thanks. good advice