I buy Missouri coated bullets, that are brienell 18, they have done most excellent in my 44 magnum, their 170 grain .401 diameter coated SWC is my choice for a Glock barrel in 40SW. Thoughts?
The coated bullets are generally pretty forgiving and often work well even when the size and hardness isn't quite right. The .40 bullet you mention will work great in most barrels since it's coated, but still best to slug yours to be sure. It only takes a minute; I like to use soft lead muzzleloader round balls, and drive them into the barrel with an aluminum rod. Measure the resulting diameter of the lead slug, and buy bullets at least .001" larger, .002"-.003" larger is fine too as long as the loaded round isn't too fat for the chamber.
For a bare lead bullet, that 18 Brinell is a bit hard, and if your barrel slugs at .401", it's gonna lead with a .401" bullet. If it's .400" or smaller, it'll generally shoot OK. Biggest .40 cal barrel I had was a Beretta 96, at .403", it wouldn't shoot any commercial cast bullets without severe leading.
