The problem with buying vs casting your own is often poor lube from commercial casters, unnecessarily hard bullets, and bullet to gun fit. There are a few commercial casters that use a reasonable hardness alloy and some use a decent lube, but I only have purchased bullets from one caster that allows the customer to determine the diameter. Not meant to discourage purchasing, but be aware that a too hard bullet that doesn't fit your gun will give a skewed impression of the bullet's design/performance...
The 45 Colt bullets I cast are from 20-1 alloy (or equivalent) sized to fit the cylinder throats of my gun...