Opening Up A Lee Cruise Missile

[Good Cheer]

This is part of the project of rejuvenating a pitted up 6.5x53R. As the bore gets larger a larger bullet is needed.
What I want to do is open up one cavity of a Lee cruise missile mold. Thinking that the best way is probably to use steel wool on an old bore brush, Clover compound, keep adding more steel wool and spin until done. Anyone got ideas?

[waksupi]

Try something easy first. Try bumping up the nose of the boolits in your sizing die to fit the throat. Made a big difference in my Swede.

[Good Cheer]

Apologies, use of the term "bore" was intended to convey the inside of the barrel rather than the land to land dimension. The bore and groove diameters are increasing in the barrel. The Lee mold is already too small. I'm looking for best means of opening up the cavity to create a bigger diameter bullet. If this rascal ever will shoot ever without just eating the boolit. I am hopeful however and will soon (hopefully) begin paper patching for it.
Any way, I haven't been able to figure out how to do the aluminum mold other than to polish it and try casting / measuring, polish it and try casting/measuring. Maybe a new brush with valve grinding paste whipping around would be more aggressive (quicker) but also would probably not be as evenly accomplished as with steel wool and changing the orientation of the blocks as the spinning is done.
Anyhoo, was hoping someone had done did this and already observed mistakes, had that lessons learned thing.

[MT Gianni]

No way would I use anything that did not fit the mold perfectly. If I decided that this was the must do, rather than having a mold cut to the necessary dimensions, I would put a screw in the end of a cast bullet in that mold chamber and use it with Clover. Measure wear and replace as needed.

[nanuk]

there have been a couple good articles about doing just that

the "Impregnating" the boolit with lapping compound appears to be the safest route.

Go slow, check often.

[JeffinNZ]

I successfully lapped out the frontal area of both cavities of my Lee CM. What I did to keep track of progress was start by taking a sulphur cast of each cavity. This gave me a base line as I wanted an extra thou from memory. Anyways, by lapping and taking successive sulphur casts I was able to measure accurately the net increase in girth without having to heat the mould and let it cool again using lead.

[leadman]

This is easy to do with lapping compound and the boolits from the mold. I use the sprue plate as a guide to start a hole with a small drill bit. Usually use a drywall screw and turn it with a cordless screw driver while applying slight pressure with the handles. Go slow and cast new boolits frequently. Kitchen cleanser like Comet will also enlarge it slowly with the side benefit of no oil to deal with in the cavities like with lapping compound.
Might it be easier to size down a 7mm boolit?