The round ones firmly press the patch against the barrel wall and really do a good job of removing the dirt and solvent. Some, for shotguns, even have a springy action that really compress the patch against the barrel without it being too tight. The slotted ones, not so much. So I can't understand why the slotted ones are the only kind that come in cleaning kits these days. And it is really getting hard to find the round ones anymore. You can order them from the internet of course, but they are not no easy to find in the LGS in a variety of sizes. For example, at a sporting clays range a friend takes me too there is a cleaning room set up for the members to use before going home. All the jags put out for folks to use are the slotted kind. What's up?