June 9th, 2013

Reverse Your Rocket Tool for a Smoother Inside Neck Chamfer

Want smoother chamfers on your case-mouths? Here’s a simple tip that can: 1) remove the sharp edge left by chamfering blades; and, 2) create a smoother entry for your bullets. Smoothing the inside chamfer can avoid nicks on your bullet jackets, and can also make bullet seating more consistent.

If you are using a 45° rocket tool on newly-trimmed brass, start your inside chamfer with two or three turns in the normal cutting direction. Keep the tool centered, and use light-to-moderate pressure — you don’t need to remove a lot of brass. After your cutting turns (which should reveal a shiny chamfer line), take out the tool, inspect the neck and remove any small brass chips or shavings.

Now here’s the secret — put your tool back in the neck and go in the reverse direction for a couple partial turns. Again, be sure to keep the tool centered and use a light touch. The reverse rotation of the rocket tool inside the case mouth will burnish and smooth the chamfer. Next you can make a quick spin with some fine steel wool held in your fingers. Don’t grind away — you do NOT want to get rid of all the carbon in the neck. As a last step we run a hand-held nylon brush in the neck for 2-3 quick passes to further smooth out the chamfer and remove any residue from the steel wool.

Accurateshooter.com Neck Case Chamfer Brass prep

We think, if you use this procedure, your will find that your bullets seat more smoothly and consistently. That can improve accuracy and help avoid mysterious fliers.

Accurateshooter.com Neck Case Chamfer Brass prepYou can use this same technique even if you prefer a sharper angle chamfer tool for your initial inside-neck chamfering operation. Reverse your tool gently a couple turns to burnish and smooth the cut. And always remove brass chips and shavings before you run the tool backwards (in the non-cutting direction).

Don’t Forget to Smooth the Outside Chamfer Too
You can also use the backwards rotation trick on outside chamfers to smooth and soften the sharp edge. A little steel wool, applied judiciously, can help here. If you are chamfering a large number of cases after trimming, you may want to tumble the brass in corn-cob or walnut media after the chamfering procedure. Tumbling further smooths the chamfer. You want a nice, smooth chamfer with no burrs or sharp edges.

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