An important consideration to keep in mind is that the M14/M305 rifles were originally designed to fire a bullet weighing around 150 grains, which leaves behind it the optimal pressures to cycle the action as it passes down the barrel.
Heavier bullets like the 180 grain soft points that are most common at hardware and sporting goods stores in Eastern Canada generally use slower burning powders to start those bullets down the barrel without creating dangerous pressures upon ignition. A consequence of that is that they produce higher pressures as the bullet passes further down the barrel, which results in the action being cycled more violently than would be the case with the faster burning powders. That could eventually wear down the op rod, which is no longer an inexpensive part to replace.
The easiest solution is to stick to lighter bullets, though hunting bullets under 180 grains aren't always the easiest to find in some parts of the country, so stocking up on a few boxes of soft point ammo might be prudent for the hunter. Also, in a pinch, one could simply shut off the gas valve and use the rifle as a bolt action to safely use the heavier bullets. In the past, there have been specially designed gas system plugs/nuts (not sure of the part name) that could be installed on the M14/M1A to bleed off some of the pressure when firing heavy bullets, but I don't know if they were adaptable to the metric threads used in the Norinco clones.
I hope that sheds further light upon the matter at hand.
