 The first two options were (and are) extremely dangerous.Later Colt revolvers had a notched hammer that would fit over an intermediate safety pin located between chambers of the cylinder on the back of the chamber when all cylinders were loaded, thereby obviating contact of the hammer with the percussion caps until the single-action hammer was intentionally cocked.In 1839, a hinged loading lever and capping window became standard for new revolvers and was retrofitted to the older designs.