Powder coating is the best bet or anodizing. But I have access to a powder coating booth at my local makerspace.

Love the powder coating.  I am planning to paint mine up but have been doing research on painting aluminum before I do anything

really beautiful! A section of black pvc to cover the barrel might be attractive.

Well for me it was free bc a member helped me do it. I'm not sure what the cost is but it is worth it. The priming stroke is a bit smoother too.

Caliburn with Powder coated priming bars, polished barrel, rubber grip, and custom muzzle break.