We dont' get birch, but Ramin and maple. Both in 7/16", 1/2" & 9/16" and work jsut fine in the larger bores for range rods or for cleaning rod. Just put a rod tip on one end. I use .308 brass or other brass that fits, up to and including magnum bras with the belts turned off. Drilled and tapped through the primer pocket/flash hole, they hold 10X32 jags just fine.
: Birch will also work just fine.