I read once, they worked just fine with jacketed bullets, but that cast bullets would foul the gas port. True, or not, I do not know - that was written up in Guns&Ammo or Shooting Times several (or more) decades ago.

I would personally have preferred a short, 3 round box magazine like used on the old Winchester Semi Autos- but - the Rugers did appear to be a VERY handy bush rifle - a little 'thick' for a saddle scabbard, though.