What is a 'hardcast' bullet?

[HardDrive]

Does this simply mean the bullet is formed by creating it from molten lead using a cast of some kind?

In a related topic, can someone point me to an article about sectional density of bullets?

Thanks.

[Jeff Higgins]

"Hard cast" describes a bullet cast from lead alloyed to increase its hardness. Pure lead is quite soft and only really suited to a few particular applications as a bullet metal. Round balls from muzzle loaders, paper patch bullets, and some groove diameter slugs used in muzzle loaders, such as the Thompson/Center Maxi-Ball. It is soft enough to where it leads the bore very easily even at lower velocities and pressures. I think it runs somewhere around 4-5 on the Brinell Hardness scale.

Tin and antimony are commonly used to harden lead. Sometimes one or the other; sometimes both. Tin has the happy added benefit of making the bigger bullets fill out better in the mold, but is far more expensive than antimony. The addition of either can significantly harden lead, with some mixes getting up into the 20's on the BHN scale.

Common alloys are 10:1 lead/tin, 16:1 lead/tin, and 20:1 lead/tin. Antimony is typically used in far smaller quantities, more like 2%-5%, but still results in harder bullets. A 10:1 lead/tin mix (if I remember correctly) will yield a BHN of somewhere around 12-15 or so, where about 3% antimony will do the same.

Another way to harden lead bullets is to heat treat them after casting or to quench them in water as they drop from the mold. Either method is dependant upon having antimony in the mix; tin does not respond to either method. Such heat treating can actually get the BHN up into the 30's. A lot of high power cast bullet shooters do this in their target rifles. Interestingly, they will degrade over time and return to their original hardness. They will also lose hardness when passed through a sizing die.

For the rest of us, BHN's over the low 20's are pretty useless; the bullets become quite brittle. BHN's in the 10-15 range have proven the most usefull for all-around shooting in most handguns and BPCR's, where the vast majority of cast bullets are used these days. They work great for hunting, and are just soft enough to obturate to fill the bore when fired.

So there you go. "Hard cast" is one of those old terms that no one really knows the origin of; gramatically challenged, but descriptive. Kind of a mainstay of the shooting world. Rather general, as it covers a broad range of hardnesses, but most folks know what you are getting at. The details can follow from there.

[HardDrive]

Thanks Jeff.

This came about from discussions of people using a .357 for hunting large game. The suggestion was using a 170+ grain 'hardcast' bullet to maximize penetration, and hopefully get an exit wound.

There are obviously larger calibers more suitable for the job......

[Jeff Higgins]

Depends on what "large game" is. Mid West whitetails are taken with .357's quite often. Not the first choice, but it will kill them. The hard cast bullet, of the right shape, is the correct choice. A 158-170-ish grain Keith or LBT style would work. Straight, deep pentetration is the objective when hunting with a handgun. These designs provide that along with significant permanent wound channels. They essentially cut a hole, rather than part tissue.

No handgun caliber kills with "shock" in the way some believe high velocity rifle bullets do (they really don't either, but that's a discussion for another day). They have nowhere near the energy of even the most anemic rifle rounds. So you get your choice; expansion or penetration. The former has failed every time I counted on it; the latter never has. Put a hole all the way through them, and they go down. That is what a hard cast semi-wadcutter bullet does best.