I mentioned this at BattleRifles, but it may be of interest to some of you looking for a quality alternative to the pricey, hard to find (albeit quite collectible) Brookfield unit.
I have a few of Mike Sadlak's spring guides and am very impressed. They are around $35 and are nicely made. The only reason I'm plugging them is 'cause they are good, and I want to give support to those supporting the M14/M1A platform with real (not gimmicky junk) components.
Sadlak Industries
860-742-0227
Nadeau Industrial Park
Unit 7
PO box 202
Coventry, CT 06238