Well here`s my 2cents, If building new loads I check every round (I use all 6 chambers) for 18 rounds, if no signs of leading I check each cyl full until I get the load shot up.
As far as chamber & throat sizes go Doug Guy has the correct tools to get em all the same & clean up the forcing cone.
I had em to ream cyl & clean cones on 5 of my revolvers & so far I`ve got improved accuracy (as far as I can tell , I`m not as good a shot as some)but the bit of leading that was happenin in some throats & cones has ceased.
I can now wipe the powder residue off & go with it as the bores are shiney & I can see steel in the throats, I do run a patch thru just to satisfy my slight OCD .
I cast my own & use Randy Rat`s TAC 1 & TAC X , also use White Label`s Carnauba Red , all 3 are very good lubes & I behoove anyone to try em if lookin for a lube .
Although if ya don`t got any lube sizers powder coating looks attractive & some have it down to a science!!
Now , you`re gonna shoot hard commercial stuff , can I suggest a good micrometer to measure em with so you`ll KNOW the dia. instead of relying on the label. Once ya measure em ya can check em in the throats , they should be interference fit , not falling thru, that`s bad from the get go & probably will lead no matter what.
IF, no , WHEN ya lead ya barrel here`s how to DELEAD it .
Get your favorite solvent out & wet the throats & bore down, let it soak a bit (I use Ed`s Red & give it at least 15min) while the stuf is soakin take an old bore brush & wrap some copper mesh pot scrubber( unwrap it so it`s flat& ya can cut to size)(take a magnet with ya to the store to make sure it`s all copper & not copper coated steel) around it so it fits snug, you`ll be amazed at how fast the lead is removed.
I use a lead away cloth wrapped on a popcicle stik to keep it flat on the front of the cyl & frame ( note : higher end loads & this will vary with alloys will keep the lead blown off the face & frame to a point)
& as far as hardness , I rarely cast handgun boolits over 14 bhn & most are in the 10-12 bhn range, if ya start putting a lot of tin & antimony in the mix ya can almost get to jacketed costs.
Rifles is a different story all together!!
Read all ya can here: CastBoolits.com
Enuff for now , GP100man