From a safety standpoint, before shooting any gun which was made with chambers shorter than 2.75 inches (the LC Smith and maybe the Flues), it is critical to measure the chambers and determine whether they are still their original length. If it has had the chambers lengthened, as has been done to quite a few, you then need to know whether the wall thickness at and immediately beyond the new chamber is adequate to withstand shooting shells of ANY length. If the chambers are still their original length, just shoot 2.5 inch shells.
