I would guess that there is something wrong with the end grind of the teeth.
If the teeth are gashed to center with a simple vertical face, they will not cut very freely, so if you cannot improve the angle by regrinding with more rake, then a slightly concave end relief seems to work better, IMO.
If you are using a knee mill, the vertical head could be slightly out of adjustment and causing end of the endmill to drag along, too. It is something to check.
First you get good, then you get fast. Then grouchiness sets in.
(Note: The opinions expressed in this post are my own and are not necessarily those of CNCzone and its management)