i fought feeding problems for quite a some time when i first started into the AR platform. of course, being a cheap ass, i bought cheap mags - all of which needed feed lip adjustments. after learning more about the feed lips and bending them just so, the problems seemed to disappear.
i dig the M4 ramps, but you can do them yourself. for simple explanation, according to my research, the M4 ramps are a gesture towards avoiding feeding issues while under field use. you know, another way to avoid a problem while a soldier or officer is under fire... as far as i can tell, if the mags are properly adjusted and made from a quality manufacturer, the M4 style ramps will never be an issue.
HTH.
septic tank