Not really any choice, I started out with the intention of powder coating.

With the advent of bullet powder coating, the envelope of possibility has expanded, and the probability of success is greatly increased without needing too much technical skill or experience.

I am using a polyester powder coat, and I powder coat twice.

So for choice, choose a colour.

Coating adhesion is good, bullet hammers flat with no loss of coating.

Load development with these bullets was with soft lead, BHN 8, with a single coat of polyester powder coat.

I got minor leading in the barrel, there was a lead smear on the leading edge of the grooves, which cleaned up easily.

I cast the next batch from a bucket of reclaimed range lead, used two coats of polyester powder coat, and they were BHN 12. There was no visible leading in the barrel after 15 rounds, but the first few patches came out grey, and the barrel was clean soon after that.

Lead hardens over time. Let your lead bullets sit for a few weeks, and then check hardness. My as-cast, water quenched 12 BHN was 16 BHN a couple of weeks later.

I suggest that if you want to exceed 2100 fps, you should use wheelweight lead or similar, to get the BHN to 16+ .

But if you have a sufficiently heavy bullet, you don't need to go any faster.