Modern .44 Magnum ammunition with 240 grain bullets loaded to approximately 1200 FPS shouldn’t do any harm to your gun, given any “reasonable” amount of use. The bane of early .44s was/is the heavier than standard bullets. I’d stick with US-brands, and take care to keep the gun clean and operating freely. JMHO, FWIW.

Very nice revolver you’ve got there. Hope it brings you much enjoyment.