There's been no widespread failures of the Zamak 5 material in the nearly 20 years Henrys been producing their guns using the material.
I've never seen a single report of the material cracking or wearing out in those guns.
The castings are quite well done through a sophisticated process, the rimfires are typically very accurate.
The guns continue to function.
They're not made of traditional materials, but they don't have to be to work & keep on working.
The steel centerfire frames are forged 4140 steel, which is an industry standard.
The non-steel centerfires use a hardened bronze-aluminum alloy.
The loading method is a matter more of tradition than inferior/superior.
I find it a helluva lot easier on my thumb during longer shooting sessions.
I waited years for mass reports of widespread Henry rimfire failures that never came.
I've now given them as first rifles to two younger people I regard highly.
I quit worrying about how well they hold up.
Denis