Good question. I believe it is 5 degrees per side, but Brownell's sells two basic cutters, for various calibers, in 5 degrees and 11 degrees. The factory typically uses something around 7 or 8 degrees. The 11 degree cutter won't work. It will leave a two step forcing cone. Not good. The 5 degree will clean up the cone nicely. I have used it satisfactorily on all my .357 revos. I have started using it on my .45 revos as well. When I recut my 610 (10mm), I had to use both the .38 5 degree cutter and the .45 5 degree cutter. The original forcing cone was pretty bad. Now it shoots fine.

If I could get a good 7 or 8 degree cutter I would probably use that instead.

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Tom