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Old November 3, 2005, 11:09 PM   #5
Unclenick
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Join Date: March 4, 2005
Location: Ohio
Posts: 21,020
Dave Manson’s tools will have superior quality and probably be more inherently resistant to chatter. However, I bought the Brownell’s tools back in the early 90’s before Dave left Clymer to set up his own shop, and have been satisfied with them with the addition of an odd trick. I once started a crown on a sporter barrel that developed a chatter pattern I just couldn’t clear cutting by hand. Rather than risk chip scoring by going muzzle-up under the drill press, I adapted the cutter to an 8” long ¼” hex drive flexible extension shaft inserted into the chuck of my battery powered drill/screw driver set to low gear and run slowly. The flex shaft, slightly bent off axis, winds up just enough to jump the cutter across chatter grooves and so cuts the peaks and levels them until cutting smoothes out.

Military surplus barrels typically have funneled rifling at the muzzle caused by steel cleaning rods; particularly the segmented kind. I use a hacksaw to cut back the muzzle as much as is practical to remove the affected rifling, then use the 90° cutter to remove any error in squareness from the saw cut. Then I apply the final angle crown cutter (and chamfer the outside with a file). If you don’t square first before cutting an angled crown, aside from looking crummy, you will bias the cutter to one side, lean the pilot to its limit, and get a crown funnel that is slightly taller on one side than the other. This guides muzzle gasses a little unevenly as they escape around the back of an exiting bullet, and can cause measurable group size increase (see Harold Vaughn’s Rifle Accuracy Facts for why).

Nick
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