After reading about several folks shortening their barrels I decided to take it on
Started with a .223 Ultra barrel at 24".
Used a pipe cutter to mark my line at 20 inches.
Used a hacksaw to cut barrel off following the groove from pipe cutter
Then a file to remove cut lines and square (took my time with saw so it was easy)
Then 220 grit, stapled to scrap wood then 320 grit.
Next I used a end mill bit to counter sink the crown. Wish I had gone a little deeper.
Then hand turned a silicone grinding bit (fits dremal tool) and then polished with dremal.
Then warmed the barrel and cold blued it.
see pics below
Hopefully the weather will be a little more cooperative next week so I can shoot it.