I'll have to check it again and see if its the wires that was causing it not to fit. I thought for sure that it was the size of the batter though. The barrel was hitting the battery before the foregrip was even close to hooking on.
Thanks though the information. I'll give it another shot when I'm home from work.
Actually, one quick question that hopefully someone can answer. Would the JG M4 S-system rail and foregrip fit on the w4-1? I'm not a huge fan of the all plastic foregrip. Plus having the rails on the sides/top/bottom would be nice.