Modifing a mould

[abunaitoo]

I have a Lee 430-310 mould that I want to extend the nose on. Reason for doing it is I need more taper to clear the rifling, and I still need to keep the overall length of the round the same.
I'm toying with the idea of reshaping a drill bit to the contour of the nose I want. Then using it to drill the new shape into the mould.
Anyone tried something like this????
Think it would work?????

I know everyone will just tell me to buy a custom mould and be done with it. But I kind of like trying things that may not be such a good idea.

[Buckshot]

............If it did not work all you'd be out was the mould, but you would have also gained some usefull insight and experience. Possibly also how to do it differently to make it work. There are a few basic pitfalls from the very beginning. One is hand grinding each flute of a drill bit evenly to shape, and then sharpening the altered flutes.

I don't know how you intended to hold the cutting tool (or the mould for that matter) but if you had a decent drill press you could grind a single fluted tool to alter the nose, as I believe you're talking about running it stright down into the cavity?

.................Buckshot

[abunaitoo]

I have a lathe.
I was thinking I could spin the bit and shape it with a grinding stone or something similar. Cut the flutes back to sharpen.
Hold the mould in a vise on the drill press and run the bit into it.
I'm not sure how nice it would come out, but if the general shape is good, I'll be happy.

[missionary5155]

Good morning [smilie=s:
You can modify a mold with just a drill. BUT I would recommend hunting up a friend with a drill press.
This is a Lee 90320 .358 150 SWC modified to about a 180 (depends on the mix).
In soft lead out of a 3.5 inch 357 mag (6grains Unique) smacks with some authority. Never pushed it faster as it will complete penetrate big wild dogs at 30 feet.
Did this with just a drill bit (largest I had that just cleared the grease grooves) and a hand drill. Use some masking tape to help guide it at the sprue plate area and for depth. Locked the mold into a padded vise. Had a small square handy for visual refrence and SLOWLY removed metal. But it works and as I am 5000 miles away at the end of the supply chain it was worth the time.
God Bless you Mike