Bore Tech’s innovative Proof-Positive Rifle Patch Jags eliminate the false indication of copper fouling that is common with all traditional brass jags when using copper removing cleaners.Constructed from a proprietary alloy and engineered to provide superior cleaning, these jags set the standard for effective, non-brass, 100% barrel safe jags. Are your barrels PROOF-POSTIVE clean?.17-.20 5/40 Thread .22-.50 8/32 Thread Bore Tech - Redefining Gun Care Proudly made in the USA