One could leave the crown as-is after using the facing cutter. The crown is the very end of the bore, and this is the portion that must be perfectly square to ensure the bullet's symmetrical escape. The barrel's outer edge was rounded with 600 grit paper.Ĭrowning was the last step. Back the sandpaper with something firm so it stays flat. I wasn't going for something shiny but wanted to remove any obvious scratch marks from the coarser sandpaper.ĭon't use your finger to support the sandpaper since this results in uneven sanding and rounded edges where you might not want them rounded. I started with 320 grit paper and ended with a light polish with 1500 grit. Start with a medium grit sandpaper, then work your way to finer grits until you get the desired smoothness / polish. Small metal shards can slip down into the gap between the pilot and the grooves, and oil will help prevent them getting snagged and dragged by the pilot.Īfter squaring the end of the barrel with the facing reamer, there might be "chatter" marks, grooves, lines or other cosmetic imperfections. Remember, the pilot contacts the lands of the bore, not the grooves. Apply lots of oil to the surface being cut when facing or crowning to float away the shavings so they don't scratch the inside of the barrel. Now you can start squaring the end with the facing cutter. Here again, clamp the barrel in the vise with only a small portion of it protruding to protect it from errant file strokes. I like to mark the end of the barrel with a magic marker so I can watch progress and make sure that filing is more-or-less even or removing metal from specifically where desired.
Once the barrel is cut off, do some initial cleanup and squaring with a file. Brownells said a lathe or saw is preferred, but you can use a grinder or cutting wheel if you take it slow and don't raise the barrel's temperature too much. That way you won't run the risk of scratching the 'good' part of the barrel if the hacksaw slips. Be sure to place the barrel deep into the vise so the upper surface of the barrel is below the upper surface of the vise (see the figure).
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