Today I received a new (old) pocket watch in the post - an 1898 J. G. Graves Express English Lever. I bought one of these earlier in the year, but it ran very fast and has since stopped running at all. It was cheaper to obtain another one in working order than it was to have that one repaired. The old one, although running fast and off-beat, was clearly running at (or should have been running at) 18,000 bph, or 5 bps. This new watch has been running for about 12 hours now and is keeping pretty good time so far, but it's running at (apparently) 15,400 bph. Is this a normal or standard value for watches from this time? I've heard of 14,400 bph and 16,200 bph but not 15,400 bph, and a quick web search doesn't seem to find any reference to it.
Even if it is a standard rate, isn't it odd that two watches from the same manufacturer, of the same model, and from the same year, should have a different movement?