the first thing i do when i assemble a lower is to sit down and watch tv for about an hour (usually after dinner). while i am watching tv i will work the pivot pin, and take down pin. after about 100 times on each pin they are smooth as butter. just like everything else that touches it needs a "break in period", you can do this over a period of 10 years (working the pins only when needed), or in a matter of an hour while watching tv. usually the next day i will do the same thing right after dinner only this time messing with the trigger. a couple hours of screwing around makes for a much better time at the range.
some of my pins (just about every manufacture known to the ar world) have been super tight, some not so much, but after about an hour they are all smooth as butter.