How to Check a Rifle Bore

Over the course of time, the integrity of a rifle's bore can become compromised. This occurs in the form of powder residue buildup, which reduces the diameter of the barrel, and also in the form of pitting and erosion from the force of explosive rounds and the cumulative corrosive effects of burning powder. Checking your rifle bore for these damages is a relatively simple process.

Things You'll Need

  • Bore gauge
  • Cleaning rod
  • Felt patches with powder solvent
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Instructions

    • 1

      Remove the bolt from the rifle and look through the barrel from the breech end toward the muzzle, lining up your eye below the back of the scope. Check for powder residue, scratches and any other abnormalities.

    • 2

      Clean the bore completely by running patches with powder solvent up and down the barrel with the cleaning rod. Run patches from both the breech end and the muzzle end of the barrel.

    • 3

      Fit the proper caliber fitting to the plunger of the bore gauge and insert it from the muzzle end after the bore is clean. Extend the plunger until it reaches almost to the firing chamber. Do not extend it into the chamber itself, which will throw off the measurements.

    • 4

      Take a measurement at the end of the barrel near the chamber, record the reading, and then move the plunger in one inch to take another measurement.

    • 5

      Continue taking measurements of the bore along the barrel, obtaining one measurement every inch or so. The readings will give you a sense of the bore's condition, where there might be pitting or erosion. Record the measurements carefully and take note of any variations along the length of the barrel.