Longevity is another matter entirely, the underlug is the weak point on the Handi, the 500S&W is known to set back the underlug when using full pressure loads extensively and the reason why I reinforced mine(see underlug improvement in the FAQs. That and flex in the action itself, although I've never had a problem with straight wall chamberings, it shows itself in high pressure bottlenecked rounds as a hard to push barrel release button and a gap between frame and barrel face after the shot(before opening the action) and brass that won't fully rechamber without full lenth resizing first, neither of which I've experienced with 60kpsi loads in the 405 Win and 444 Marlin or 50kpsi loads in 45-70 or 500S&W.
Tim