This might help, good photos and tools needed. Winmag may have a better site and/or link.
http://www.ar15.com/forums/topic.html?b=3&f=4&t=226782
Don't know if I posted this correctly but the AR 15 Forum seems to quite a few topics on building your own and/or tuning your own. Worth a look anyway.
Short walk this morning, Gypsygirl is now napping. Begining to think the ice will be here till spring. mmm. spring thaw...