Apparently, they were just as bad, if not worse, than the pistol. The reason for this was that they were often given a larger - longer and thicker - cylinder for a higher BP charge which increased the likelyhood of gas escape. There was little or no provision for a forward hand grip on the rifles either and, given the relatively low power of the shot, most were issued as cavalry carbines - for 'single-hand' shooting.
Side note: At this time military thoughts were that revolvers of any type were considered useful only for those who had no need of a long arm and only one hand for a gun, the other hand holding a sword or reins. They were for short range personal defence. Their advantage was immediate, rapid weight of fire at that short distance. (Then came reloading!)