As far as I know, there are no cock-on-closing current rifles. The closest you can come to that is the Ishapore Enfield mentioned previously - the Enfields are cock-on-closing and that one is available in 303 or 308.
All cock-on-closing rifles cock on the forward bolt stroke, not on downward bolt rotation. All cock-on-opening rifles cock on upward bolt rotation. So alternative descriptions might be "cock-on-bolt-push" and "cock-on-bolt-rotation" There is one currently made straight pull rifle that I am aware of and I do not know when it cocks - the previous straight-pull rifles (with one exception) were never safe to shoot - and still are not.
Cock-on-closing is mechanically simpler, FWIW, but you're pretty much out of luck for a new one, I'm afraid.
Tom