I want to cut down a shotgun and would like to try using this tool to crown the muzzle:

https://pacifictoolandgauge.com/muzzle-facing-cutters-nopix-/763-12-gauge-muzzle-facing-cutter.html?search_query=shotgun&results=71

https://pacifictoolandgauge.com/muzzle-facing-cutters-nopix-/763-12-gauge-muzzle-facing-cutter.html?search_query=shotgun&results=71

Yes, I understand that I could just use files, but it seems nice to use a professional tool.

I do not have access to a lathe, and so wanted to ask if a tool like this is OK to use with a hand drill, or if it is designed to be used with a manual tap handle. Basically, is something like this designed to cut at high speed with a drill, or is it designed to cut at low speed. I know to use plenty of cutting oil when doing this in either case.

They are inserted and turned so that it cuts.  Since you are only taking the lightest of cuts it is done by hand. The idea is go get consistent even pressure.   Its rather like a deburring tool used on brass, all you are doing is cleaning up the edge to remove any burrs. One could also use a cone shaped object and polishing compound like Tormek honing compound.   If I was going to spin a cone shaped tool with honing compound and a drill it would take material off fairly slowly but the tool you selected would only be used by hand and to spin it with a power tool would take off material really rapidly.  Just a few turns will be all that is required.  I had a gunsmith years ago that did that with S&W revolvers and re-cutting the crown significantly improved accuracy.

Shotguns with the exception of slug guns this effort might not really be that much of an improvement.  If you have something cone shaped you can put polishing compound on and spin with a drill you already own that is likely sufficient.  Brownell's has the drill & tap and bead for shotgun barrels.

Thanks for the help. Is there anything wrong with using a tool like that to cut say a quarter inch of metal off the barrel end though? Say I want to cut the shotgun down to exactly 20". I was thinking Id use a hacksaw to cut it to say 20 and a quarter, then use files to square it as best I can, and then use the muzzle facing tool in a drill to cut it back down to exactly 20".

I'm really just looking for advice on how to use the tool without leaving a ton of chatter marks in the metal - if that is likely, then I'm better off forgetting the tool and just using my files.

@eugene_stoner
OP
Go to https://4drentals.com/ , they have a video on how to use almost all their tools. There's a couple vids on how to cut, crown/face, and thread for chokes.

4D actually states the opposite:

@AeroE

@AeroE
In their videos, they show using both a hand drill (@ 0:45) and lathe (@ 0:56) for the facing tool.