Quick response which hopefully answers your question: Too lazy to look up the exact time span, other than it was roughly 9 months during 1900 (225000 - 250000 or so) during which time that cocking piece was used on new production rifles and carbines. Years ago, before Mallory & Brophy, it was though to be "correct" only on M1899 carbines, but that was proven false. Interesting but not rare, and, having caused more problems than it solved, use was dropped.