First, the instructions...
1. mod the magazines. cut off the four plastic 'spacers' at the front of the magazine. grind down the sides of the magazines so that all the writing/bullet symbols are flush. Take apart the magazine. cut the follower, just two quick cuts, there is a line right at the back center of the follower, youll know what i mean when you are cutting. if you dont do this the mag will lock the bolt open with one round left. (DO ALL OF THIS WITH THE PLASTIC SAW) after that get the drill bit out, and cut the mag catch.

2. mod the magwell, with the magazine taken apart(empty) it should fit in the magwell, a tight fit. with the grind stone grind down the inside of the magwell untill the magazine slides in easily. the back of the magwell need to be rounded like the back of the magazine. i can still use the original magazine bot it wobbles a little, im thinking of trying ar10 magazines sometime,
Sounds bad enough already--but wait until you see the results





From:
http://fnforum.net/fn-scar-17-magazines-t26987-50.html