Dremel bits for recrowning 177 and 22?

Don't use the cylinder, you might try McMaster Carr under die grinding burs.

something like these

https://www.amazon.com/uxcell-Mandrel-Mounted-Grinding-Polishing/dp/B072F8VGV5/ref=asc_df_B072F8VGV5/?tag=hyprod-20&linkCode=df0&hvadid=198070022856&hvpos=1o3&hvnetw=g&hvrand=15478853351916209681&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9033255&hvtargid=pla-351574379657&psc=1

I did see a video where a twist was used run in reverse and the crown area looked great

I did buy same this type rubber grind polishing on Ebay from China and they work well, you can just twist them in your fingers

Anything that would be called a sanding bit or grinding bit is too coarse. The type marflow references is probably fine though—a rubber material impregnated with a fine abrasive. Another good approach is using a round head brass screw slathered with a fine compound like J-B bore paste. It’s slow but purposely so to ensure no burr remains. 

#6 (.177) and #8 (.22) ROUND head brass screw and lapping compound...

For example, here's one I did earlier this week using a brass screw and J-B. This method yields really good results if you take your time. Notice how distinct the lands and grooves are.

Well if you want to create a deep bevel, you can start with something more coarse and then finish up with a brass screw & compound.

Just a couple of things to take into consideration:

1. Take care not to create an uneven bevel. A coarse cutter will tend to grab your workpiece, removing more material on one side...and because it's aggressive, it happens very quickly. You want to orbit your drill as you go which randomizes any lateral bias you're applying, and that helps to create a uniform bevel. If instead you try to hold the drill perfectly in-line with the barrel, you will end up with a lopsided bevel.

2. The deeper the bevel, the more likely it will develop some unevenness. If the muzzle will be exposed (no shroud / LDC / muzzle brake), a deeper bevel provides some inherent protection to the crown from bumping the muzzle into something hard. Otherwise there is no reason to make it any deeper than is necessary to remove any burrs. The one pictured above is pretty shallow but is still deeper than was necessary.

I did the brass screw and lapping compound method with great results on the Lw barrel in the Boss. Really doesn't take long, but not something to be rushed anyways.