I have read that about the Arisaka being one of the strongest actions. Probably the reason there are not more custom rifles made on this action is because of the way it looks. Face it, it is not as attractive as a 98 Mauser or a pre 64 M70.
What I do wonder is what there is about it that makes it so strong. If the same design that makes it so strong, if there is anything to that, could be incorporated into a modern rifle and the safety made more attractive and easier to use, it seems like the design could be utilized for a really strong and functional action.
I have also read about the rechamber job to .30-06. That story has been floating around for years. I don't know if there is anything to it or not.
