There are two ways to make cores for swaged bullets – casting cores and cutting cores from lead wire. I chose to cast cores because I am already set up for bullet casting.
Casting bullet cores is much like casting bullets, except I’m not as worried about the finish and look of the slug when it drops from the mold. The cores will go into a swaging die where they will be sized to the specific weight needed for the final bullet. For example, to create a 55 grain bullet, I subtract the weight of the jacket (i.e. approx 9.7 grains for a jacket made from Remington .22LR brass) from the desired weight to know what the weight of my cores needs to be.
The lead used for cores needs to be soft – pure lead is perfect. Core swaging requires tremendous pressures, and soft lead ensures that the die isn’t damaged. Since I use wheel weights for my cores, I pre-sort my wheel weights and only use stick-on weights for bullet cores. The clip-on weights can be used for swaged bullets; I ingotize (is that a word?) the stick-on weights and the clip-on weights separately so I have an ample supply of soft lead for bullet swaging.
My purchase of BT Sniper’s .224 swaging system included an 11 core mold designed specifically to make cores suitable for ~55 grain bullets. Alternatively, Brian can provide molds that cast heavier cores (i.e. to create 62 grain bullets).
Like bullet casting, molten lead is poured from a ladle into the mold. I won’t delve deeply into that process here, but feel free to look at my bullet casting page for more details. Suffice to say that my lead casting equipment is primitive… but it works fine and it’s cheap. The cores drop from the mold heavier than my target weight of 43.7 grains. As already noted, the raw core will be swaged to its final weight in another step.