The only reason why rimmed cartridges should be considered more suitable for Handis is they're generally low pressure and they work best in ejector barrels which have a bad habit of causing failures to eject, but H&R no longer makes ejector centerfire rifle barrels, hasn't for a few years, so rimmed or rimless in a high pressure round is a moot point. Even ejector barrels can be converted to factory extractors, so that makes the FTE problem a non-issue, the rim isn't a saving grace, it's the pressure they operate at and the breech thrust created, I've had FTEs in my 405Win H&R with max loads, it's a rimmed round also. On the other hand, I had no FTE's with the experimental 300WSM at mid level loads under 60kpsi, it has a rebated rim, those loads were just too much for the frame due to the huge case head and caused internal action flex, but they never did FTE in the ejector barrel.
Tim