Thing is, people today don’t read books. They just pass internet rumors to each other.
November 1851 Col Colt gave a scientific paper before the British Institution of Civil Engineers, a large section of which was dedicated to the discussion of chain fires.
Colt describes one modification he made “the Author, after much reflection, to give a slight chamfer, so as to deflect, or thrown off at an outward angle, the fire which expanded laterally across their mouths. The reason for this alteration was, that when the lateral fire met the rectangular edge of the orifice of the chamber, the angle of incidence being equal to the angle of reflection, the fire was conducted downward, or inwards to the charge; but when the flame struck the chamfered edge, it was directed outwards away from the charge. Unimportant as this alteration may appear, it has proved so effectual, that if loose powder is placed over the charge, in the adjoining chambers, it is not now ignited when the pistol is discharged. These and other improvements have brought the fire-arm to it present safe and effective condition, and the Author believes, that no casualty can occur, nor that more than one charge can be fired at one time, if the metal is sound and the arm is properly loaded”
He also mentioned chain fires occurring when he enclosed the rear of the chambers. He called it a “shield” I also think one of the improvements Colt alludes to was the open top of the colt revolvers. A solid frame will direct the path of burning powder right back to the nipples.
Chain fires will start at the front, and at the back.
If I'm not shooting, I'm reloading.