By Randy Garrett
If you’re casting for fun, going slowly is fine — even part of the fun — but these tips will still help you turn out top-quality bullets.
1. Use a bottom-pour melting pot Ladling metal from the melting pot to the casting block greatly increases the potential for a dangerous alloy spill and the alloy temperature will be far less consistent. Introducing a ladle to the melting pot will produce greater temperature variation in the melt as the ladle draws temperature away. When using cast-iron, multi-cavity blocks, it’s a great convenience to remove the L-bar from the bottom-pour melting pot and place a cast-iron loaf pan, such as a Lodge Loaf Pan, under the bottom-pour nozzle. This allows the caster to slide the block from one cavity to the next without concern of molten alloy running off the top of the sprue-cutter and compromising base fill-out.
When the cavities are filled, the block can simply stay on the loaf pan until it is time to cut the sprue and dump the bullets. When using a cast-iron loaf pan be sure to pre-heat it as well as your blocks.
2. Monitor your alloy content If mixing your own, weigh the tin and antimony added to your lead so each new batch of alloy is similar. Whether mixing the alloy one pot at a time (not recommended) or mixing your alloy in greater bulk and pouring it into ingots for later use, keep a close eye on the resulting bullet weights and diameters. Any significant variation in the amount of tin or antimony will show itself as a change in average bullet weight and diameter. Assuming consistent casting technique, significant differences in average bullet weight or diameter from pot to pot, or batch to batch, will always be the result of varying alloy content. A reasonable percentage of weight variation would be about 0.25 percent.
A Lodge Loaf Pan provides a block resting position below
the nozzle and offers stability and safety.
3. Drop the hot bullets into a bucket of water This practice will help to keep drop-damage from occurring. Dropping bullets directly onto a hard or padded surface is a leading cause of bullet denting since the temperature is still high enough to cause them to be soft. If the hot bullets fall through one foot of water, they will be much cooler when they hit the bottom and less likely to dent. This can be especially critical if one’s casting alloy and block do not produce bullets larger than the desired finished diameter. Also, most alloys will produce more consistent hardness when dropped into water for quick cooling and dent protection.
4. Get the right sizing die Since the chamber throats of revolvers are often a little larger than bore diameter, correct sizing diameter should reflect the diameter of the chamber throats more than bore diameter. Otherwise, blow-by will tend to cut the bearing surface of the bullet as it moves through the chamber throat, decreasing accuracy. The small amount of “sizing” occurring as the bullet enters the barrel is of no consequence to either accuracy or pressure.
A S&W 629 with 0.431″ chamber throats. This is the
proper size-to-diameter for this gun. The chamber
throat diameter is more relevant than bore diameter
when casting bullets.
5. Use cast-iron blocks Compared to aluminum blocks they are far more durable and are better at holding temperature than aluminum blocks. The temperature of the block will have much to do with the temperature of the bullets when they are dropped from the cavities. Significant variation in their temperature will compromise the hardness and consistency of the bullets.
6. Consider buying your casting alloy from a foundry It’s virtually impossible for bullet casters to mix their own alloy and come anywhere close to the purity of the finished alloy from a good foundry. It’s true some foundries don’t bother with small orders, but if you know another bullet caster you just might be able to split the purchase and meet their minimum requirement. Many foundries do have an alloy mix on hand for bullet casters. It usually runs about 2 percent tin and 6 percent antimony, with the remaining 92 percent being pure lead. Given the time and expense required to cast quality bullets, guaranteeing the purity and consistency of your alloy makes sense.
Bullet casters may vary their bullet alloy for casual shooting, target-performance or big-game hunting loads. Through proper alloy content and casting technique you can create the finest in every one of those categories. It’s indeed possible to tailor your bullets to the exact requirements of the job, and accept no compromises along the way. Only the person who skillfully makes his own bullets can take credit for the performance of his ammunition.