Pietta Remmie screw sizes

[Pomona Pete]

I found a pietta remington that had been buried for awhile (don't know why it got buried) and I got it apart and all the screws out but would like to run a tap through them before I put new components in it.  Does anyone know what size taps that are used?  It appears that there are only three different sizes but none of the dims match any threads in my books.  Thanks guys

                                                                                                                   Pete