Not every round, no. I have a 100 round case gauge and what I typically do is fill it up as I go. Most of the rounds I put in there sit ever so slightly proud (I'm talking half the width of the rim is sticking out) and if I press down on them with light pressure I can usually get them to sit flush in the gauge. I haven't really thought of this as the culprit, since the rounds that feed and load fine and the ones that jam me up all look identical in the gauge.
It does feel like I'm squeezing them in the gauge when I press down, however. So maybe that's got something to do with my problem