How to create bullets with two hardness partitions?

[Naphtali]

I have a problem to solve. I want to make cast bullets with very hard base and pure lead nose -- about two-thirds base and one-third nose -- cast for rifle shooting .50-caliber black powder "soft point."

I can think of several ways of doing this, but I have no idea what is the simplest, the least expensive method.

I have been considering casting the base partition as a hollow-nosed wadcutter with annular grease grooves. The "nose" would be steeply conical.

With a second mold having the final bullet shape, preheat the mold by casting-and-discarding or partially dipping into molten lead pot. Place the base partition in its proper place in the finish mold, then complete the bullet using pure lead.

Among the things I'm concerned about are:

1. Will partitions become one bullet without using a swaging die? I'm not referring to a sizing die.

2. How to assure correct ODs for each partition?

3. What configuration to use for lubrication grooves?

4. What is the correct shape to allow partitioned bullet to be accurate while having pure lead nose not bearing on rifling?

5. Who can make the molds?
********
I don't have tissue-paper feelings. I'm interested in solving a problem, and I probably haven't identified all the problems I face.

[JBMauser]

This was the topic of an article in Handloader Mag perhaps one issue back from the current issue.  The author simply used a small dipper to pour a dollop (martha stewart cooking term for a smattering) of pure lead into the mold which filled the point of the bullet and then dumped WW or harder lead on top to fill out the mold.  The two leads joined and were properly melted together.  It held together well and gave very good expansion on impact.  This was recomended as the ultamate hunting load next best would be paper patched I suppose.  Bottom line, it was easy to do with regular molds and two lead posts going.  JB

[Shootingamigo]

Mountain Molds makes molds for this application. Says they are no more expensive than a 2 cavity mold. ALOT less fuss with a mold for the application.

                                   Shootingamigo

[John Traveler]

Naptali and all:

Lyman used to (about 20 years ago) offer two-piece bullet molds for doing exactly what you propose:  Cast a soft-lead nose, and a hard-lead base.  the two pieces were them swaged together into one integrated unit, sized, lubricated, and loaded.

The nose portion had a "tang" that fit closely into the base portion that had a "socket", and on swaging together, were securely held.

I dunno if they still offer it in their custom bullet mold line, but you can certainly ask!

I would hazard a guess that at today's machine shop prices, you are looking at probably $100 to $150 minimum to machine those mold blocks from some old mold blocks.  Even more, if the machinist had to make his own blocks to start with.

HTH
John

[Shootingamigo]

Lyman or RCBS havent offered custom molds for quite some time. Mountain mold is the only maker that I know of that makes these molds. There isnt a post type flange to hold these together. Rather it fuses the 2 parts together. The directions on the website seem straight forward though. RCBS does offer uncut mold blocks.

                                                     Shootingamigo

[MTNGUN]

Yes, I can make such a mold.  For 50 caliber it will require the XL blocks which cost $70 in aluminum.  Casting these softnose bullets is a slow process but the quality of the bullets is high.  As long as the hard alloy is poured hot, say 800° plus, then it will bond to the pure lead nose.

Or you can use the 2-pot method as Ross Seyfreid described the the Handloader article.

These softnose bullets do work very well.

http://www.mountainmolds.com

[Johm D M]

Are you certain that you need expansion? Everything I have shot with a 50 muzzleloader has gone down right now. It intrigues me for up to 40 cal. but I wonder about it for larger applications? John.

[carpediem]

I believe NEI offors a mold for what you are looking to do.

[HWooldridge]

I have seen this done with epoxy joining the two halves.  You will have a mold for the nose and one for the base with a tongue and socket for the two to mate.  Runout can be an issue so the slug should be swaged after joining to insure concentricity.  However, this exercise is probably more trouble than it's worth unless you just want to do it for fun.

[lewisgoldstein]

There is another way to have a two hardness bullet, with oven hardening.
Example: with a 30 cal. bullet 1 1/4 inches long
Drill an aluminum plate with a lot of 30 cal. holes, just barely larger than the od of the nose end ~2/5 length of the bullet.
Stand the bullets in a tray, and put the aluminum block over the top of the bullets.
Put this assembly in the oven and heat like a standard oven heat treating.
After the appropriate time, take the assembly out of the oven and add enough water to quench the lower half of the bullets, the water level not hitting the still hot aluminum plate.
Let this assembly slowly cool.
The bullet bases will be oven quenched hard, and because of the hot al. plate, annealing the noses, you have a soft nose.
Use an alloy of WWs with an added 1/2 % tin for best results. - Lew

[Doctor Sam]

Take a look at http://www.prbullets.com

I bet he has what you are looking for.  Premier bullets for muzzleloaders.

Doctor Sam