If reloading range brass it's a good way to make sure the round will go into battery. Its insurance. It's also best to chamber check the rounds with the actual pistol barrel chamber used. Most malfunctions I see are due to poor quality control on reloaded ammo. I use a U die for 9mm, 40 S&W and 45 ACP. It also aids in preventing bullet set back in .40. If my reloaded ammo can fall into the barrel chamber and fall out then it's good. Sent from my iPhone using Tapatalk