You shouldn't have to polish the feedramp or anything else on a new gun. You're doing the manufacturer's work for them, for free. Back in the old days, the better makers tried for a 0% return rate. Now, they are just about all run by beancounters. They determine how much time is required for final fitting vs. how many would actually be returned for repairs. Since most people just b*tch but never return the gun, they come out ahead that way.