Bullet Sizing

You’ll want to pull the breech plug and push the bullet through. When it’s sized properly, you won’t be able to pull it back out of the muzzle with your fingers. I like to be able to push the bullet into a clean barrel with my thumb and index finger. Once it goes in with thumb and index finger, I’ll use a ram rod and push it through to the breech. I like pretty light pressure on a clean bore to push it through. After a few fouling shots, I may tighten the die a half mark or so for the desired loading pressure on a fouled bore. Desired loading pressure varies from barrel to barrel and person to person. I’ll test until I see what the particular gun likes, and try to keep loading pressure consistent after I see what works best.
Jeff Hankins has videos on YouTube showing how he sizes bullets. Most here are using the same, or a very similar process.