I believe that if you shoot jacketed bullets they should be 0.239''. For cast bullets you should ''slug'' your barrel to get the correct diameter for that barrel only.
Only what the reload manual for the bullet you are shooting. That is,,,,, Sierra manual for Sierra bullets. Barnes manual for Barnes bullets, and so forth.
264 Win Mag for across the bean fields.
12 gauge pump shotgun with 00 buck for close work.
44 Mag revolver with speed loaders for closer work.
USMC Kabar for really close work.
My grandfathers and uncles would make gaiters out of tractor or big truck inner tubes.
Length would be from crotch to top of instep. Hang them off of your belt