When you say "no trigger guard", can we safely assume that it has an "encased" or spur trigger and is single action only? If so, there were several dozen manufacturers of these types of revolvers and at least 300 known "brand" names. If you cannot post a picture, at the very least post a complete description and list all the markings on the gun and where found. Patent dates can also be of big help. If it is totally unmarked, there is very little chance of IDing your piece.