By 1860 it looks like he had it figured out:
Special Order 94
War Department, Adjutant General's Office
Washington, May 18th, 1860
The Board of Officers appointed by Special Order 94 to "examine and report upon certain improvements recently made in Colt's Revolving Fire Arms," having made the examination as directed, submit the following report:
"The arms were loaded and capped, and then loose powder was scattered around the percussion caps, and also around the balls, when they were so fired without producing any premature discharge, or communication of fire from one chamber to another."