help with gas thru foregrip

[trugama]

i just purchased a classic mag...and i have no clue where the gas thru foregrip goes...can somebody give me a little insight ?

[askman]

vertical asa needed

If you bought a classic mag without vertical asa, you need to get one. On the body rail, there is a place you can drill out. You can go with vertical asa plus gas through(20 for asa and 15-20 for gas through) or I've seen some gas through grip that directly screws on to the body rail. (I've seen it on ebay for about 12 bucks a piece)