The .40 Cal/10mm patch jag is specifically engineered for cleaning .40 Cal barrels, including but not limited to .40 S&W, 10mm, .41 Magnum, .400 Carbon and .41 Action Express. These patch jags apply a solvent- or bore paste-treated patch against the barrel and into the rifling to mechanically remove carbon, plastic and copper deposits from the bore. For demonstration purposes, we used this patch without solvent and pushed it through the barrel once. As evidenced, these jags provide superior cleaning performance compared to others available on the market. The proof is on the patch. Beyond cleaning, these jags are also utilized for oiling the bore for storage and removing oil prior to firing. Our rifle jags are compatible with all rods featuring standard 8x32 threads. Additionally, we recommend purchasing USP bore paste and round TCS patches for .30 Cal - .45 Cal rifles and pistols. TCS round patches are ideally sized for use with this jag, while other patches may result in fit issues. Square patches are not recommended for use with our jags. Precision-engineered patch jag crafted from high-grade aluminum alloy for enhanced durability and optimal performance in cleaning and maintenance applications Solvent-resistant, durable O-rings Compatible with all standard cleaning rods