I would like to increase the diameter of the current bullet I'm using and am looking for suggestions for a simple cheap way to do this, The only power tool I own is an electric drill.
My current bullet is the BACO 400gr money bullet which drops at about .409", I would like to increase this to about .410 if possible and see if it shoots any better at that dia.
Cheers
Mike.

Check out my video about one way to do it.

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Different alloys do cast larger or smaller.   I can't remember where I found the data, but the harder the bullet the larger the diameter.    For example Lyman 375449:  lead  .3773"; wheelweight .3779"; #2 alloy, .3785"; linotype, .3789".     Probably holds true for other bullets as well.    

George

George Babits wrote on Aug 10^th, 2021 at 9:35am:


Linotype is alloyed to give the best (largest) size of type when cast, as well as being hard enough for multiple uses.  Other alloys for type are harder and a bit more durable.

Mick, you could try belling the case mouth just a little bit so that you can feel it drag on the walls of your chamber as you slide ithe cartridge in.

If you want to increase the diameter of a bullet without attacking the mould with a power tool, you might go over to the Cast Boolits Forum (their spelling, not mine) and look up the process called “beagling” which was developed by a frequent correspondent who uses beagle as his screen name.  This technique will give you a couple of thousandths increase in bullet diameter without permanent change to the mould.  If you ask for help, there are lots of guys there with experience using this strategy. 

Froggie

I have found being larger than the groove diameter works out very well. Myself I like my own bullets being 1 thousandths per-side over the actual groove diameter size.  In all honesty a 1/2 thousandths per-side depending on alloy, casting methods, temperature, shrinkage rates, how the mould is being held closed each time is one that is just damned near impossible to be able to precisely maintain. The more important thing for me is to look if the bullet might be smaller in diameter than the diameter of the freebore. If so the base should be at least 1 thousandths over the diameter of the freebore itself. So at times one might have to overlook the actual groove diameter size. Something has to be guiding the back of the bullet into becoming central to the bore and that is what the freebore and the leade in angle are for. One for the front and one for the back and both are required to establish a proper bullet fit.