Are you seeing this problem in Windows? Chrome and Firefox for Windows don't render fonts perfectly. Other operating systems don't have this issue. Try changing the em size of your font to 512 before downloading it. You can do that in the IcoMoon app. In the font tab, press "Preferences" and you'll find the em size under "Font Metrics". If changing the em size to 512 didn't help, you could try changing the ordering of the urls in your @font-face and pull up the SVG font's url before the other ones.