Firelapping bullet size

[bubbadoyle]

I have a Ruger SRH 454 casull.  I shoot mostly 45 colt out of it.  The barrel has a very definite constriction and I am thinking of firelapping.  I have no real experience with slugging the bore but I did push a bullet I cast from stick on wheel weights through and It measured about .4510 - .4515.  I have the lee 300 grain gas check mold as well as the lyman 454424 mold.  The lee mold casts at .452 and the lyman at .454.  Which bullet should I use for my firelapping and should I size the bullet before or firelapp unsized.  I have looked through all the pages here trying to find this answer as I know your time is valuable to you.  I appreciate the wealth of information you have posted on here and all of time you have spent answering questions for us beginners.  Thank you.

[Veral]

  Use the smaller bullet, as it will gain at least .002 in diameter when the compound is applied.  This if you are using the LBT bore lap kit, which also contains very detailed instructions on lapping any rifled firearm.  If you aren't using the LBT bore lap compound, I don't recommend that you lap.  And I hope you don't mind my candid response, but I've done a LOT of experimenting in this field and have developed a compound that is fast cutting while doing the job smooth from beginning to end.  There is a lot of advice out there from people who don't understand precison or what's actually happening inside, and much of that advise takes thousands of rounds worth of wear out of the throat.  No one needs that.