heat treating bullets from mold vs oven

[Jack Straw]

I know this particular topic has come up here before, but I thought I would bring it up again. There are some new members whose opinions I would be very interested in reading (Randy Garrett this means you!!!)

I've tried both but still have questions as to which method is superior. Some of the questions still in my mind are: Does one method produce a more consistent bullet? What about the effect of sizing either before or after hardening? Some say bullets must be sized before treating or else sizing softens the bullet and thus negates the hardening process. And what about the use of gas checks -- if, for instance, I'm building .44 loads and size my bullet at .429, heat treat, then attach a gas check and lube with a .430 sizing die, am I adversely affecting accuracy by having a .429 bullet tipped with a .430 gas check, or is that size difference negligible? Or should I size with the gas check and heat treat it too?

I know its a lot of questions most likely with long answers, but I really would be interested in everyone's opinion. Please feel free to address any issues I haven't asked about.

Thanks in advance!

Jack

[Randy Garrett]

Jack,

The best way to heat treat your castings is to simply drop them from a hot block into cold water. Also, there is no need to size the bullets first, as the bearing surface just does not suffer from being sized after the hardening process. If they did suffer from being sized after hardening, one would find that barrel leading would become a problem. And in our very considerable experience, our bullets produce only trace leading in the barrel, which does not effect accuracy even over a long shooting session, and is easily removed by simply dry brushing the barrel (this is due to the hardness of the alloy, as softer alloys tend to smear when brushed and therefore are much harder to remove.) Indeed, in my personal 44 Magnums (14) I only shoot hard-cast bullets produced as described above, and I NEVER require more than an occasional dry brushing to clean the barrel. Assuming one is a consistent caster and does his casting in a rhythmic manner and does not vary the time of sprue cutting significantly, one will find that his bullets are hitting the water at a very consistent temperature. If the alloy in question is arsenic enriched and low in antimony, one will achieve about 25-Brinnell hardness without the brittleness so common to high antimony alloys. The method described above has proven to be the most consistent method, and it has the added advantage of making life easier. If more complicated measures yielded better bullets, believe me we would have adopted them years ago. As far a gas-checks go, if you like them go ahead and use them. However, I don't they offer any particular advantage in handgun loads that do not exceed about 1450-fps. for rifles, however, they are a must if one is to get really good accuracy. This question of bullet hardening is a classic example of simplicity being the art of sophistication.

[Randy Garrett]

Dumping a whole tray of hot bullets into cold water causes unnecessary dents in your bullets, due to them bumping into each other on the way to the water. Remember, when they are hot, they are soft! Also, a large number of hot bullets hitting the water at the same time super-heats the surface water, somewhat reducing the quenching effect.

[Paul B.]

Randy. The RCBS cast bullet handbook shows a mesh basket used to drop the bullets in the water after removing them from the oven. The bullets do not bump into each other when using this basket.
I size the bullets, and apply gas checks when called for, prior to heat treating.
Hardness runs from the upper 20's to lower thirty's Brinnel, depending upon how much chilled shot with arsenic I add to the melt. Seems like you can't buy that stuff anymore. My alloy is 10 lbs. wheel weights (cleaned of course) one lb. linotype, and from 1/3 to 1/2 cup of chilled shot.
Works for me.
There are some articles at: (www.sixguneer.com/paco/favorite.htm) on hunting with cast bullets. It's a real good read. It is in 3 parts. The author prefers the "drop in the water as you cast" method, and uses an alloy of either 16 to 1 or 18 to one chilled shot and 95/5 solder. I haven't tried that allow yet, but I plan to in the not too distant future. I've already taken several deer with cast lead in the 30-30, and seriously doubt I'll ever see the need for a jacketed bullet in that round again.
Paul B.

[Randy Garrett]

Paul,
Using a mesh basket is definitely better than placing them on a tray. The need to attempt oven tempering depends upon a number of things including the caloric characteristics of your blocks. We manage to achieve similar hardness without the added step of oven tempering, however we use extremely heavy cast-iron 6-cavity Hensley & Gibbs blocks which help considerably in efforts to maintain constant temperatures. Since you are using wheelweight metal, you may not need to add chilled shot as the wheelweight metal comes with arsenic already added. However, it sounds like you are getting good harness, hopefully without brittleness, so more power to you! We torture test our casting with a free-falling sledge hammer to test for brittleness. We find that our practices allow our bullets to be so battered as to assume the shape of a coin without shattering. Sometimes really hard bullets will shatter when stressed beyond their inherent hardness. You might want to give this a try. As to sizing and gas-checking prior to heat treatment, I just don't think that is necessary. Certainly it doesn't hurt anything, but you are then required to run your bullet through the sizer again to lube them, and that's getting to be a lot of extra work. Unless you are certain that this results in less barrel leading, you could forgo that step.
Best regards, Randy Garrett www.garrettcartridges.com