Four of the most popular handgun cartridges in the world share nearly identical groove diameters - and this .357 / 9mm brass jag cleans all of them. The .357 Magnum, .38 Special, 9mm Luger, and .380 ACP all have grooves between 0.355" and 0.357", making this one gun cleaning jag that covers your entire pistol rotation. The pointed brass tip holds a cleaning patch centered and pressed firmly against the bore walls for maximum fouling removal.
Pistol bores foul differently than rifles. Lower velocities mean less copper fouling but more unburned powder residue and lead deposits - especially from .38 Special wadcutters and unjacketed .357 loads. Semi-auto 9mm pistols also accumulate carbon around the feed ramp and chamber throat. A brass jag pushes a solvent-soaked patch into direct contact with these deposits, dissolving them faster than a loose patch draped over a slotted tip. The difference is clear on the first pass.
For bore cleaning with this jag, 1.25" to 1.5" square patches fit best - just enough to wrap tight around the tip without bunching. After your brush work, alternate wet and dry patches on the jag until they show no color. Finish with one oiled pass for protection. This brass jag handles the daily gun cleaning that keeps a carry pistol or range revolver reliable.