I reluctantly step into the fray to add my 2 cents worth:
1. On the carrier, make sure it is clean before you attempt to preload the torsion spring. I rotate the spindle to the first notch after the guide stops the carrier and try it. If it seems too weak, rotate 1 more notch and secure it. I do not increase preload beyond that setting.
2. The cartridge guide is to me the deepest mystery in the 99 legacy. There are more than 2 dozen of them, and none to my knowledge ever marked with their caliber at the factory. Having the correct one can be crucial as gnoahhh previously stated. I would look for evidence that yours has been replaced before I started a treasure hunt for the right one. The pictures in Numrich are in some cases notional, as you are discovering.
3. On several occasions, I have solved feeding problems by modifying or changing the auto cutoff to control the position of the round to be chambered. This usually happens only with rifles that have been altered. The difference in cutoffs is far more subtle than in guides, but does exist.
