doublegunshop.com - home Forums General Discussion DoubleGun BBS @ doublegunshop.com Tempered (?) Shot

The discussion about "hard" versus "soft" shot put me in mind of an experiment that I conducted almost thirty years ago.

At the time, E. H. Harrison was writing in The American Rifleman about the merits of "tempering" ("annealing"?)cast bullets in order to increase their hardness. Significant increases in hardness were noted. Since that time, this procedure has become pretty well accepted and several cast bullet companies now offer bullets that have been so treated.

It was at this time that a friend indicated to me that he was very disappointed in the patterns that his Damascus-barreled Parker 10-gauge gun was generating with black powder loads. The loads seemed to be reasonable; about "bulk for bulk", as I recall, using Goex Ffg black powder, 1 1/4 ounces of shot, Remington plastic cases, Remington primers, and Remington plastic wads. When I asked him what shot he used, all that he could tell me was "They are #4s". I asked to see the shot. It was sorry! "Soft" did not even begin to describe the stuff. I had no difficulty in compressing its pellets using a needle-nosed pliers and just my thumb and my index finger.

It was then that I had my brainstorm. I asked whether I could "borrow" the shot over the next week. With a quizzical expression, my friend agreed.

When I arrived home, I noticed that my wife was away. This was my chance!

I put the coffee can containing the shot into the oven and set the temperature for what I recall was 400 degrees. I let the shot "heat soak" for about 30 minutes. After the "soak" I removed the shot from the oven and immediately dumped the stuff into a bucket of cold water. I then removed the shot from the water and let it air dry on sheets of newspaper.

If the shot was sorry before it looked even sorrier after being heated. It was a dingy shade of gray and it was rough in texture, the shot's graphite coating having been removed by the quenching bath. However, when I tested the shot for hardness: Revelation! Not only could I not even make a mark on the pellets using a needle-nosed pliers, but I also had great difficulty in making even minor marks using a standard pliers and very heavy hand pressure. This stuff was hard!

I had no graphite on hand so I made do for lubricating the shot with WD-40. The shot was now ready for experimentation.

The next weekend, I had my friend load the modified shot into his shells using his "standard" load. Again: Revelation! I can't remember ever seeing a 100% pattern but the patterns that these loads generated certainly seemed to come close. I have never seen patterns that demonstrated a better combination of density and evenness than the ones that this old gun generated with these loads.

Has anyone performed similar shot-hardening experiments? If so, how did they turn out?

You are one brave guy! I'd never, ever try a stunt like that in my wife's stove. I once used a bottle brush on a long handle to clean black powder residue out of a set of Lefever barrels. In her kitchen sink; you should've seen the black stuff all over the ceiling, walls and everywhere else!...Geo

Dingelfutz,
You can only heat harden bullets that have antimony in the alloy.
Mike

If I'm not mistaken, the typical good brands of high antimony lead target shot is made in drop towers and quenched in water at the bottom.

The WD40 lubrication may help substantially in allowing the shot to get thru the choke without being badly deformed. Has anyone had much luck using GREX (powdered polyethelyene) as a group tightener?

I loaded a lot of nickel loads using Ballistic's Products buffering compound, and if I remember right I gained about 5% pattern improvements. Of course I was also rolling the wads in Motor Mica but I don't think that made much difference in patterns or the velocity, but I wasn't about to leave a stone unturned.

Anybody up on the metalurgy jump in and correct me. I remember that the hardening effect on lead-antimony alloy comes about as a function of time. The water bath is just to cool it off. I don't remember lead alloys requiring a quench. Anyone?

DDA

From what I can tell from the N.R.A.'s book on cast bullets, quick quenching encourages "small" antimony dentrites that yield higher Rockwell hardnesses than the "larger" dentrites that slower cooling yields. Hardness after casting/heat treating can increase for a time and then gradually soften again.

"Brave" might be a kind description. Thirty years ago, most of us did not have the kind of handle on the dangers of lead vapors that we do now. I would hesitate to try this experiment in a oven that is used to cook food, now, myself. Of course, those of us with non-shooting spouses are generally the beneficiaries of a certain level of tolerance.

A bottle brush? In a sink? What in the world were you thinking?

Thanks, that sounds logical. However, I wonder how "fast" and "slow" cooling vary between shot size pieces of lead alloy and bullet size. Seems to me that the time factor for dendrite growth would be the same but cooling rate would be very diferent.

Good topic and discussion!!

DDA