Extraction definitely a problem. I understand that the Browning Automatic Rifle employs oiling pads in the magazine to aid extraction.

One source I read stated that Canadianicon manufactured ammunition was appropriated by the Britishicon Army to help alleviate stoppages in machine guns. When they start designating ammunition as .303 Cdn. and .303 Brit., you definitely have a problem. Some of the British ammunition even jammed the Lee-Enfields. However, the Lee-Enfield had far better camming advantage for extraction. Probably explains why Ross returned to "cock-on-closing" for the MK III rather than adopt the "cock-on-opening" employed in the Ross Mk II**. You can definitely tell the difference.

Another issue was determining whether a Ross bolt blow-back was the result of an incorrectly assemble bolt, or, the result of clearing a miss-fire without waiting for the safety count. Again, no clear documented evidence, only supposition.