Suggestion of a couple links to add to the "Beagling" FAQ:
This is a truly outstanding writeup on how to enlarge mould cavities and correct out-of-round conditions, with emphasis on how to uniform multi-cavity moulds and tweak individual sections of the cavity.
http://castboolits.gunloads.com/show...48#post2987548
Also, a classic on advanced lapping techniques, already a sticky thread:
http://castboolits.gunloads.com/show...ture-diameters
Gear