Building bullet molds?

[Cactus Farmer]

Now that Paul Jones has quit making molds a local smith asked me if we might make a few molds. So, what do you use for block material?
I prefer iron and have studied the ductile iron sources. I even scrounged a piece of 2" about 3" long and it appears to be the continuous cast material. Striations on the outside. I chucked it up and took a light cut to true it up. Not very round it seems. Turned like cast iron but the finish is much better. This is spheroidal carbon not the flakes found in regular cast iron. They tout it as lighter than steel and stronger than cast. Ductile is the name and perhaps a clue. It comes in round, square and some rectangle sizes.
I'm thinking as a test I'll cut off a couple slabs and pin them together, cut the grooves for the handles and D&T for the screws. Then cut a flat on one side for a sprue plate and then separate them. A quick surface grind and cutting some air relief grooves before boring the cavity. A D bit for the nose profile and lathe turn the grooves I don't think I'll get rich but there is some pride in shooting bullets (boolits) that you cast in YOUR own manufactured mold.
Where can you improve on my plan?

 

[LEEQ]

Imperfections at the nose have been proven to have less effect on accuracy than those at the base. A nose poured bullet mold will produce more accurate bullets than base poured, of course assuming this is the only difference in the two bullets. Just a thought to ponder. Not necessarily the easy path.

 

[LEEQ]

I forgot to mention I am exited to see what you come up with. Both the molds and the targets! What are your first bullets looking like as far as caliber, style, and weight? There is an outfit that makes custom molds. Their website has a fancy calculator that helps you build bullets. mountainmolds.com. You should check it out. It's fun.

 

[Stob]

LEEQ is right, a nose pour is more accurate.

It is my understanding, molds are made by making the cutter, called a "cherry", and the two mold halves are separated and closed on the spining cherry to make the cut. Never seen it, but that my understanding of it.

 

[LEEQ]

You could pin the halves together and bore it on a face plate too. A self centering vise would be good for the Cherrying. I would love to hear other methods of bringing the halves together around the cherry while maintaining center. Edit Say, that website likes your choice of material for the mold by the way. Names it specific for molds.

 

[george wilson]

I can't see that he is wanting to make a round bullet. I made a conical bullet mold for a .36 caliber repro out of aluminum. I made the blocks to fit into my Lyman handles.

What I did was file a square length of W1 steel into the profile of the bullet I wanted,grease rings included. Then,I drilled a hole in the center of the 2 halves of the mold blocks. They already had alignment pins installed,and were held in a 4 jaw chuck. I "drilled" the cavity a little deeper with my W1 cutter to make the nose flat,then brought the cutter out sideways,cutting the metal away until I reached the desired caliber. I had the compound at 90 degrees to the cross slide,so I could withdraw and accurately re insert the cutter,using the graduations on the compound dial to re situate the cutter after I had measured the diameter of the cavity.

This made a very nice mold. Alas,I did pour from the base,as this was in 1974,before I knew better. However,the bullets worked fine.

The reason I made the special diameter mold was I had found that the cylinder chambers of all my Italian repros were grossly under sized,so the bullets hardly touched the rifling. I had made slightly tapered reamers and reamed all of my repros out to fit the rifling properly. The accuracy of the pistols was GREATLY improved. But,to shoot conical bullets,they needed somewhat larger diameter molds.

I posted a sticky in this gunsmith forum on how I really made a Remington 1858 model shoot like a new Smith and Wesson. It required a special mold too,after enlarging the cylinders. Aluminum works fine,but,of course,require careful handling.

 

[Cactus Farmer]

The best molds (most accurate consisantly) are lathe bored. I am thinking a 4 jawed chuck is the answer to the centering issue.
I will try both bottom pour and nose pour. To build a base pour I need to make one flat to attach the sprue plate. A nose pour will need two flats that are parallel. And how would you close the bottom? Base plug or double sprue plate? Both work,ie, hollow base molds , like minie bullets and some older pistol and rifle bullets. And with a base plug there is the option of several plugs to vary weight and to add small hollows to allow you to fold paper jacket tails into the cavity.
I have seen one nose pour that the top and bottom plates were one peice but I can't remember just what it looked like.
I'm a fan of single dipped bullets for consistantly being the same weight. I do pour from my bottom feed pots for some stuff but for the real good long range (500 meter rams) I like dipping the metal and pouring them one at a time. Those rams are tiny from 1/3 of a mile! A gnat sneeze is important to that kind of shooting. If I get that "good" I'll try the long range shooting at Raton, 800,900 and 1000 yards. I was in the pits when a fellow shot a 283 out of 300. That's 17 9's and 13 10's. We were all in awe of that preformance.
Matthew Quigley would have been proud!
I shoot 45-90,40-65 Maynard(30-40 Krag straight) and 38-55. The first molds will be 45's because there are more 45 shooters here to do the testing.

 

[george wilson]

My Lyman handles close the mold by means of the swinging sprue cutter,which also serves as the very short "funnel" to pour the lead into. This funnel fits the nozzles of bottom pouring electric lead pots. Makes for fast,easy molding. The sprue cutting,short funnel is only about 3/32" thick,so you can see that the funnel is very short,and more than anything,it serves to help you feel when the nozzle of the lead pot fits into it.

 

[LEEQ]

Great stuff, guys. Have you checked out that site for designing bullets? Nothing says you have to pay them to make molds, but it will sure help you make a design that is the style and weight you desire. If I had to be difficult, and I often do, I would make a nose pour with plates both top and bottom. I think I would go to the mill and fit two halves together with pins. Now it can be thrown in a 4 jaw, drilled and bored to minor diameter. A form tool would need to be ground for driving bands/lube grooves, and also one to cut the ogive shape. I can't see any reason why a fellow could not make a fine mold on a faceplate or in a four jaw. It's on my list after all machines are up to snuff. I will learn lots in the process(read I will screw up and figure out how to fix it or do it better. A nice swage might be a fine tool to make to go with it to help out those down under shots.

 

[swampdoctor]

I made only one single mold and I gave up while i was ahead. My inspiration was a picture of an adjustable weight mold made by Lyman. I used very hard aircraft aluminum and it did not gall like softer aluminum does. I AM NOT A MACHINIST so I experimented with boring from the bottom until I barely came out the top of the mold for a Nose Pour. Lacking proper tools I made mine from Allen wrenches that had been shaped and rehardened using Kasenit. I made different length bottom plugs which were supported by a bottom plate. It ain't pretty but it makes pretty bullets. Thats all that matters. But I have done this too: Lee makes a nose pour mold for the 45/70 that can be easilly converted into an adjustable weight mold by removing its conical shaped hollow base plug, and replacing it with various lengths of alternate plugs for lighter 45/70 bullets.