Lap before or after ordering a mold?

[Coltsmoke]

Veral, I have slugged my chamber with your kit and I'm ready to order a mold. I have a Pedersoli 45-70 Sharps. I will be shooting comp. using black powder. Will be shooting from 100yds. to 600yds. The grooves measure out at .456, so I thinking a .458 bullet would be approiate. During a match I'm thinking the barrel with expand from the heat. Would it be a good idea to make the mold maybe .460 or .459 and size the bullets down to .458 for the first part of the match and then load some .459 or .460's for the last part of the match? Is it a good idea to resize the bullet or just cast as needed and just stick to shooting one size as cast?

[Veral]

  Nice line of questions you give here!

  Fill the chamber, forget the barrel diameter.  If you get a mold from me, I normally cut the first drive band close as I can hold to the barrels groove diameter and the rest of the body large enough so loaded rounds just slip in easily.  The bullets can't tip on takeoff with this setup, and bullets should be hard, not the traditional soft tin lead.

  For all practical purposes, the barrel diameter doesn't change with heat, because the above set up is way over groove anyhow, so a few 100 thousandths inch of heat change aren't a factor.

  Get the LBT lap kit and lap the bore.  It will make a precision machine out of your Pedersoli.

[Coltsmoke]

I have the bore slugs and the chamber slugs and the lap kit ready to go. Should I lap the barrel before I slug my chamber to send to you?

[Veral]

  If you don't have a mold to make lap bullets, wait till you get the mold, but tell me you are going to lap.  I'll be able to guess real close to what the lapping will change diameters.  Ditto, if you are in any kind of hurry to get the mold.  If you have a mold to make lap bullets, do the lapping while waiting for your mold to come.