Brownells J-B Bore Compound & Kroil Kit

The Brownells J-B Bore Compound & Kroil Kit combines two proven cleaning agents into one effective system for removing stubborn fouling from rifle and pistol barrels. This pairing has earned recognition in accuracy-focused publications for its ability to tackle the toughest residue that standard solvents miss. Whether you're maintaining a precision hunting rifle, competition gun, or your everyday shooter, this two-step approach delivers results that justify its place in serious cleaners' kits.

The system works through a logical sequence: Kroil penetrates first, softening and loosening fouling buildup so it releases from the bore easier. A few patches soaked in Kroil followed by dry patches remove the loosened debris. Then J-B Bore Compound takes over, targeting the stubborn deposits that resist standard cleaning—moly residue, burned powder, and copper jacket fouling. This targeted approach means you're not wasting effort on one-size-fits-all solvents; you're using the right tool at the right stage.

After the heavy lifting is done, a final pass with Kroil leaves a thin rust-preventive film protecting your bore between range sessions or hunts. That finishing step matters, especially for rifles stored in variable humidity or guns used in wet conditions. The combo kit format saves you money versus buying both products separately and ensures you always have both on hand when you need them.

Key Features

• Two-stage cleaning system—penetrating solvent followed by cutting compound
• Removes moly residue, copper fouling, and burned powder buildup
• Kroil provides rust preventive protection after cleaning
• Proven formula trusted by precision shooters and published in accuracy publications
• Works on rifle and pistol bores

Frequently Asked Questions

What types of firearms can I use this kit on?

This cleaning system works on any rifled bore—rifles and pistols. The J-B and Kroil combination is effective on bores fouled from most standard ammunition types.

How often should I use this cleaning method?

Use it whenever you need deep bore cleaning to remove stubborn fouling. The system is thorough enough for regular maintenance and effective enough for addressing heavy copper or moly buildup from extensive shooting sessions.

What's included in the kit?

The kit contains J-B Bore Compound and Kroil; exact volumes are not specified in our current data. Contact us for specific product sizes if needed for your cleaning needs.

Do I need any other tools or patches to use this kit?

You'll need bore patches and a cleaning rod to apply the compounds through the barrel. The kit itself provides the cleaning agents.