There's so much conversation about leaded barrels , I shoot very few jacketed bullets. If the diameter is correct leading will me minimal and the other thing I do is not agonize about some lead in the barrel. If accuracy is the same I carry on, takes a lot of lead to lose accuracy. You really shouldn't see any leading with coated bullets though.
So true.
This is my Gen3 G17 factory barrel showing round bore with rounded six very smooth rifling.
And this picture shows longer than typical leade length with very smooth start of rifling. What I found shooting lubed lead bullets is that factory Glock barrel's smooth rifling and start of rifling with longer leade allows the bullet to jump deeper into the barrel before bullet base (bearing surface) engages the rifling before building pressure, during which time more gas leaks around the bullet.
The longer time it take for pressure to build means more gas/liquefied lube will be blown forward of barrel before the bullet base deforms/expands to seal with the barrel. If the lead/alloy is hard enough and diameter too small, bullet can essentially slide/skid down the barrel resulting in poor accuracy and leading.
With 18 BHN MBC 124 gr RN (Small Ball) using mid to high range load data of W231/HP-38, I did not experience leading rather fouling build up. The build up was crusty type and flaky. After 300-400 rounds, crusty build up filled the voids in the rifling to essentially make it smooth bore and accuracy started to decrease. As rcmodel recommended, I would inspect my Glock barrels when shooting lead rounds around 300-400 rounds and clean as necessary and the crusty fouling (no leading) was easily removed with Hoppes #9 solvent and bore brush. With clean barrel, I would resume shooting lead rounds with accuracy restored -
https://www.thehighroad.org/index.p...glock-handgun-see-below.847392/#post-11047664
Below picture shows flaky/crusty fouling build up after 100 rounds
My KKM/Lone Wolf/BCA barrels with traditional land/groove rifling will stay clean without any crusty fouling build up even after 500 rounds of same ammo.
When shooting coated bullets, I exercise care as to flare case mouth and taper crimp to not scrape or cut into the coating.