Boolit sizing

[Gundogblue]

I just purchased a Taylors and Co. birds head revolver made by Uberti. It’s a .357 mag, I just casted some boolits  for it with a Lyman mould my dad left me. The boolits are dropping out of the mould at 0.358 to 0.3585. According to the Official Uberti USA RATE OF TWIST CHART The bore diameter is 0.346, and the groove diameter is 0.355. So would it be best if I sized the boolits to 0.357, two thousands over groove diameter??
Thanks,
Paul

[Coffinmaker]

   Gundogblue   

Not necessarily.  Don't believe all that you read.  The ONLY way to correctly size your cast bullets is to actually SLUG your bore and find out what you actually have.  .346 and .355 are common diameters for 9mm. 

Nominal industry standard for a 357/38 is 357 groove diameter, which calls for a .358 Bullet.  After slugging your bore, next step will be to check the diameter of your chamber throats.  Throat diameter should match your bullet diameter.

[Kent Shootwell]

Plus one on matching the bullet to the cylinder throat diameter!

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[Gundogblue]

Ya know what? That’s just plain good advice, you guys are right as rain about this. When I take the gun to the smith to have the bore slugged I’m gonna have him measure the cylinder chambers as well ‘this way I’ll be sure and not be guessing. Thanks again,
Paul