I measured cylinder chambers of 2nd Gen Colt 2nd Dragoon. Used a cheap hole gauge and a caliper. Oval chambers: 0.442" X 0.448". Each chamber, axis measured on a line running from center of chamber to center of arbor hole, 0.442". Measured perpendicular to line above, 0.448". Does it make sense to ream the chambers to consistent dimensions? Can it be done by hand, (how would you get pilot to fit)? How did they manage oval chambers, (.442" drill !?) I haven't shot it, I am sure of the measurements, and, yes, each is oval in the same way/dimensions/orientation ("consistent"). Since even 0.448" mouth would be .010" to .008" under barrel groove diameter (.456 to .458"), maybe I ream for a .458 chamber diameter, (and custom bullet mold.) Bore, .440". Thoughts?