Originally Posted by RWBlue
Now if we are talking non-suppresses....
Talk to me about cast vs. non-cast. I have never really gotten into the cast thing. I tested some hard cast and used some REALLY soft cast for experimentation, but.....I never really had access to free lead or ability to recover my lead.
"Bullet casting" that wonderful avocation that fills the gap between Alchemy and Necromancy.
Rules to remember (I will take the liberty of overlooking revolvers, thereby cutting a couple of steps, and stick to single chamber/barrel situation)
It is a very good idea to "slug" the barrel with a pure lead slug (a few tricks are available for this) then measure the slug to .001 or better.
Much of what would seem common sense is actually refuted by experience and "the little details". For instance,
It would seem logical that a harder bullet would lead the bore less than a softer bullet. This, however is not the case. If both bullets were to be, say, .001 undersized for the bore (ideally the should be .001 OVERSIZED) then actually the softer bullet will "bump" up or "obdurate" to match the bore thereby sealing the hot gasses behind the bullet. A harder undersized bullet will let gasses past the base where they melt the sides of the bullet and increase leading.
That often puzzles "casual" caster/reloaders initially until someone tips them off.
OK for making SWCs expand.
I found the technique in Beartooth bullets cast bullet guide that came with a firelapping kit I bought from them. I had pondered the concept before and found so much of that little book verified my own experiences and "theories", that I am quite impressed with it.
OK assuming that we are using a bullet that is cast nearly ideal in diameter or oversized and to be sized down.
assuming we are using good wheelweights or a custom mix, depending on the gun's preference, around 12/1 to 17/1 lead/tin. We know that tin or antimony not only hardens lead but prevents it shattering on impact at velocity and can help contorl leading.
Ok the bullets are dropped hot from the mold into a bowl of ice water. This hardens them much as hardening steel. A decent mixture should come out of the icewater with a Brinnel hardness of around 20 If the need sizing it should be done now.
Let the bullets come to "room temperature" then place then in a bread pan, nose up, or some container that allows you to cover them to the front shoulderbelow the nose with "cold" water. Now take a small torch and flash the tips, one at a time until just before they melt. You can see a color change wash over the tips, the second it happens pull the torch away. This "anneals and soften the tips. let them set and load away.
The things to remember about this (and why it jives with my experience working with hot steel) Lead works like any other metal, steel for instance but it goes through all of the thermal changes in a much smaller span of temperatures.
A bullet "tempered" by the above technique will expand but remain a homogeneous unit. Trying to improve the technique by, say, using Ice water in the annealing bath or freezing the bullets before annealing will creat a "shear line" between the hard and soft parts and may induce seperation under impact.
I hope that long winded diatribe explained it well enough for the principles of what I was talking about came through.