Cast Bullet Mold Selection
Cast Bullet Mold Selection - Before purchasing a mold to cast bullets, be sure you know the following:
- The bullet diameter required for your gun.
- The metal you will be casting with.
- How you will be lubricating the bullet.
If you have a new gun, most likely you will just need whatever the standard bullet diameter is for your caliber. For example: if you have a new 30-06 rifle, you will need a mold that casts .308" diameter bullets.
However, the metal that you will be casting with also affects the final diameter of the cast bullet. From the Saeco bullet mold selection guide:
The bullet diameters and weights presented in the list
are based on the use of Taracorp’s Lawrence Magnum bullet alloy (2% tin, 6% antimony, 1/4% arsenic, 91.75% lead).
Bullet diameters and weights will vary considerably depending on the lead casting alloy used. This variation can be as much as 1/2% on the diameter, and 8% on the weight among the most commonly used casting alloys. For example, a .358-158 grain bullet might show a diameter variation of .002", and a 13 grain difference in weight.
Of the most commonly used alloys, wheel weights (.5% tin, 4% antimony, 95% lead) will produce bullets having the smallest diameter and heaviest weight, with such bullets running approximately 1/3% smaller in diameter and 3% heavier than bullets cast with Taracorp's metal. Linotype will produce bullets with the largest diameter and lightest weights. This alloy will
produce bullets approximately 1/10% larger and 3% lighter than Taracorp. Other alloys of tin and antimony, with antimony content above 5%, will produce bullets with diameters and weights falling between those cast
from wheel weights and linotype.
Alloys containing little or no antimony will cast considerably smaller than wheel weights and in some cases will produce bullets too small for adequate sizing.
Within the limitations given above, the weight and diameter of a cast bullet can be adjusted by varying the alloy’s antimony content. The size and weight of bullets of a given alloy will also vary according to casting temperature. Higher temperatures will result in greater shrinkage as the bullet
cools, thereby producing a slightly smaller and lighter bullet than one cast of the same alloy at a lower temperature.
Source:
http://www.redding-reloading.com/PDFfiles/bulletchart.pdf
So, if you are going to be casting with wheel weight lead, choose a mold that will supply you with the needed bullet diameter.
NOTE: Some resizing from cast diameters is possible with use of sizing dies, discussed later)
Some pistol bullet molds are available with stick lube type grooves, and others are available with Alox type microgrooves. If you buy a stick type lube mold, you must use stick lube to lube it. And, vice versa.
Rifle bullet designs are such that the high speed of the bullet through the barrel requires stick types lubes which are thicker, and must be applied by using a lubri-sizing machine (sometimes heated).
The bottom line is to make sure that you select a bullet mold TYPE for the size, metal, and lube type that you will be casting for.
You should also be sure to check the reloading data book for reloading data for the particular bullet weight/shape that you will be casting. There are some oddball molds available for which reloading data is hard to find.
Molds come in one cavity, two cavity, four cavity, and six cavity sizes. Not all of those are available from any one manufacturer.
Some of the more common bullet designs/molds are available from:
Lyman Products Corp
475 Smith Street
Middletown, CT 06457
Lee Precision, Inc.
4275 HIGHWAY U
HARTFORD WISCONSIN 53027
Redding Reloading Equipment (Saeco Molds)
1089 Starr Road
Cortland, NY 13045
RCBS Operations
605 Oro Dam Blvd
Oroville, CA 95965
Depending on the manufacturer, and mold quality (which most often relates directly to cost), molds are available in aluminum, steel, or cast iron. The cast iron molds are the best quality, and will last the longest. The aluminum molds start off fine, but soon wear, primarily on the sprue plate/top of the mold surfaces. Avoid sprue plates made from aluminum. The will lose their sharp edge fast, and this will result in poorly cut sprues.
Most of the mold manufacturers will make custom molds for you. If you have some old bullets that you are wanting to duplicate, send them some bullet samples, and they will make you a mold for them. Have an old gun, and can't find ammo for it anywhere? Cast your own lead bullets, and have them make a mold for the bullet size and shape.
While most of this discussion deals with metallic cartridge reloading and the bullets for those, the same applies to old black powder and muzzle loader guns.