Reloading: Economy Lead

It’s over six years since we looked at casting our own lead alloy bullets, so the time has come for brief refresher course. Regarding the process, nothing has changed, nor has the equipment required! However, quite a lot has changed regarding the availability of raw materials.

Justifying the time and cost

Casting is messy, space-consuming and an expensive project. Unless you’re consuming thousands of bullets annually, then the first task is to do the maths. A heated Lyman Lube Sizer will be £300, or £200+ for a basic RCBS version, a single calibre GH&I die set is at least £25, moulds with handles range from £45 to over £100. A Lee Pro Melt pot and pyrometer adds a minimum of £145 to the bill, with a dipper, hardness tester, ingot moulds, lube, flux, essential PPE, boxwood hammer handle and a few candles adding another £200 or so. Budget for £700 and that’s without the raw materials! If you amortise that cost over your first 5000 useable bullets then they’ll cost you about £14 per 100. Compare that with the fact that you can buy coated cast lead pills in popular calibres for between £12 and £20 per 100.

Mixing metals

To create adequate bullet hardness and reduce barrel fouling, the lead is alloyed with other metals, most commonly tin and antimony. Several ‘standard’ alloy mixes exist, the default being ‘Lyman #2’, a ratio comprising 90% lead and 5% each of tin and antimony. A ‘hardball’ version comprises a 1:1 mix of Linotype with pure lead. The final alloy being 92% lead, 6% antimony and 2% tin. Obtaining suitable lead has become the greatest challenge, with butts lead often contaminated with sand. Modern wheel weights are often unsuitable and battery lead must never be used. Linotype, once a common source of raw material is now hard to find with ‘fake’ Linotype offered by unscrupulous traders. Alternatively, a few UK shooting supply traders offer 5lb ingots of US made Linotype style alloy.

Lead alloys are toxic. Unprotected handling is hazardous and the inhalation of fumes from the molten mix is potentially fatal, making the location of your casting a critical part of the process. When handling finished bullets, the use of either cotton or nitrile gloves is essential. Casting should only be carried out in sheltered, well ventilated locations that are well segregated from food handling areas and with the use of robust personal protection such as welder’s gloves, eye and respiratory protection, stout clothing and boots, and even a blacksmiths apron.

The basic process

Molten lead alloy is cleaned with the addition of a flux – but not too much as it can separate the alloying metals. It is then poured or ladled into mould blocks, allowed to cool and ejected. The melting kit can be anything from an iron pot on a stove to an electric, self-contained system with thermostatic control and a bottom pour system that reduces the risk of contamination from impurities in the alloy.

Most non-commercial moulds have 1, 2 or 4 cavities. Aluminium or steel, they are made from two mirrored halves in the form of jaws. This two-part design allows for the inclusion of annular rings for both lubrication and crimping purposes. A hinged plate called a sprue cutter is positioned across the top, forming the bullet base and designed to cut the excess material (sprue) from the bullet once cooling has taken place.

The ‘mating’ jaws of the mould have a series of fine grooves that allow air to bleed from the cavities as the lead is added. Maintaining them is essential. The faces of steel moulds should be scoured with a brass bristle brush, alloy treated with a stiff toothbrush or nylon breech brush. Before use, the cleaned faces should be ‘blacked’ by moving over the flame of a candle to reduce the risk of ‘sticking’, taking care to remove any soot from the location dowels that form part of the mould jaws.

Cast oversize

Moulds are produced to ‘oversize’ dimensions to take account of the shrinkage of the cooling alloy. As this varies with the composition of the mix, many are designed to suit the default Lyman #2 mix. Nonetheless, the ‘as cast’ bullet dimensions vary due to changes in mould temperature and alloy composition.

At the start of the cycle, the mould should be warmed on the pot to speed the production of well-formed bullets, as the cold mould will prematurely chill the alloy, producing wrinkled runts. Casting with the moulds too hot will create a frosted finish on the bullet. If you have a pyrometer, then the Lyman #2 mix temperature should not drop below 730ºF and should ideally be 760ºF. Mixes with less tin need higher temperatures, up to 840ºF. Steel moulds retain heat better than alloy and are therefore more forgiving in terms of the rate of production, whilst faster heat dissipation of alloy moulds enables higher output rates.

Ejection

I prefer steel, as they’re also less vulnerable to damage. In order to eject the bullets, the sprue cutter needs to be operated. Firmly tap it as near to the axis line of the pivot as possible. (Repeatedly striking downwards will force it against the mould body, damaging it, whilst striking upwards can bend it, leaving a damaged surface or ‘feathers’ on the base of the bullet.) If the bullets cling to the mould, gently tap the corner of the mould half that contains the bullet. Experienced casters often ‘throw’ their bullets into cold water. This process causes rapid surface cooling, which increases the surface hardness of the bullet.

Taking shape

To produce a consistent calibre diameter, smooth bearing surface and add lubricant to the annular rings, most cast bullets are partially swaged. This is known as lube sizing. The bullet is forced through a sizing system called the GH&I set. The body reduces the cast bullet to the desired diameter, whilst openings in the body feed lubricant at high pressure into the one or more rings around the bullet. Plain (no groove) cast-types are often rolled in lube after being swaged to size. The best forms of lube need warming to be used and most makers of Lube Sizers therefore offer a heater unit as an option. The stick of lube is located in the press body. The process is simple, buy a GH&I die set to match the calibre and nose profile you’re casting, (length does not really matter), insert it into the sizer press and start pulling the handle, the first few bullets will not be fully lubed and will need recycling. If the top annulus is a crimp ring, then you will need to control the depth of the press, making sure that all the bullet is still sized. Swarf and lead shavings should be regularly cleaned from the die and press. Job done.