New Bullet Mold

[mnovinger]

Made a mold today for my Win 94 30-30.  Bullets weigh 160gr.  A nose rider with a nose diameter of .300 and base diameter of .310.

[JScott]

That mold looks terrific.  Did you make the sprue plate as well?  I've never seen a three cavity mold; only one, two, four and six cavity.  I believe that at  one time 8 and 10 cavity molds were also available.  Very nice work.

JScott

[mnovinger]

I make the sprue plates from cold-rolled steel. With my set-up, I use 1.5, 2, 2.5... up to 4 inch mold blocks. These blocks are made up in batches. Like today, I'll grab a set of blocks that have most of the machining done. With a small caliber bullet like this one, 3 cavities go well into a 2 inch block. I'll cut the cavities using a chucking reamer that has the shape of the bullet ground into it (a cherry) then make the sprue plate. Then its on to testing and tweaking if necessary.

[JScott]

You're more than a hobbyist aren't you?  Do you have the equipment to grind reamers/cherries?

The only cat I know that can do things like this was a tool and die / model maker at IBM in Colorado for 27 years.

JScott

[mnovinger]

When I lived in Colorado, I had a Brown and Sharp Universal grinding machine that I used with an indexing fixture to grind the cherries. Back then, I sold molds under the business name of Mike's Bullet Molds LLC. There was a lot of old 3 phase equipment in my shop then that I picked up for the price of scrap. When I moved to Indiana, it didn't seem smart to spend $2000 to move a machine that I only paid $450 for so I sold or scrapped all the old 3 phase stuff. Now I wish I had moved the Brown and Sharp. I still have not found a high-speed grinder with the accuracy needed to grind the cherry. One of these days, I may try a tool post grinder on my lathe.

The old way to make a cherry is to turn some drill rod in the lathe to get the shape of the bullet then mill in your flutes. Harden the cutter then get out the stones to sharpen. That process takes a day to do. The process I developed allowed me to make a cherry in 20 to 30 minutes. I created an Excel spreadsheet that let me play with the dimensions. I entered the dimensions and it told me how much the bullet would weigh. Then I would put the dimensions in a CAD program and make a print of the bullet along with all the measurements needed to do the grinding.