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vicvic
August 6, 2006, 07:21 PM
how deep should it be? does it matter?

cntryboy1289
August 6, 2006, 08:33 PM
Most of the time, a crown is cut back only a small amount, but there are those that will back bore it reduce the sound output. What exactly do you have in mind for the gun?

If it is a target gun and you want to protect the crown, use a target recessed crown. Cut it .125" deep or so before finishing up the outside.

On a 11 degree crown, I cut them close to .200" deep.

vicvic
August 6, 2006, 09:17 PM
so here it is. i bought one of those barrel facing /crowning tools from brownells. i faced the end of the barrel on my a303 but im unsure of how deep to go with the crown. will going too deep affect anything?

cntryboy1289
August 6, 2006, 09:38 PM
Not as long as you keep everything concentric and don't leave a burr. You should be limited by the cutter though as to how far it will cut and leave the outside edge clean and straight.

Unclenick
August 6, 2006, 10:01 PM
Harold Vaughn, in his book Rifle Accuracy Facts, describes having experimented with every crown form from square to taper to the traditional sporter's toroidal section. He feels he proved to his own satisfaction that it made no difference at all, provided the crown is symetrical about the bore axis.

Some, like the square crown, are easier to cut. Vaughn declared the origin of the popular 11 degree benchrest crown a mystery. He thinks a benchrester confused the fact 11 degrees is the maximum angle a subsonic boattail can have without creating extra drag with somehow positively affecting the muzzle gas jet's impact on an exiting bullet. It doesn't. It might as well be 10 degrees or 14 or 30 or 7. Just keep it axisymmetric.

Nick

JohnKSa
August 6, 2006, 10:20 PM
The depth and geometry of the crown have virtually no effect, symmetry is more important.

People get too freaked out about crowns. The last rifle I hand-crowned on my kitchen table with some fine grit sandpaper wrapped around the nose of a 9mm Mak bullet put 3 shots into less than half an inch when I got it to the range.