I have seen japs converted to cock on opening, dehaas's book makes reference to an article on the conversion, E mail me , outbackengineering@gmail.com, and I will find the magazine issue date for you, but I believe it was in a Rifleman from the 40's or 50's, not sure where it might be archived for print or download, I did know a fella that wound up with a couple hundred jap actions without bolts, and was fitting 03 a3 bolts, they cocke d on opening, looked strange as well!