I've never heard of the Savage 99 having feed issues - it must of had a 'foolproof' spool magazine so to speak compared to the Mannlicher etc?
I'm no mechanical guru, but looks to me the cartridges were completely supported completely within the spool.
I know from this forum that if not using the 'correct' nose shape this would cause a jam in a Mannlicher; so was this a 'design' flaw in that system by not having full support - & how easy was it to rectify if different projectile were to be used?