Well, I'm an idiot. I tried one more time to google up some trace of it, and found that it's a feature in the mod
FN FAL - SA58 (plus Kukri). I downloaded it a couple of years ago, so I completely forgot that part. It isn't very big but man, is it a blast! I love the FN FAL a lot too, a 7.62 NATO beast of a rifle, which also makes a great sniper. It and the FN SCAR-H are perfect for when your 5.56mm rifle just doesn't have the stuff to deal with your enemies at higher levels. The Bone Zone is located maybe a half mile northwest of Ten Pines Bluff. The icon is a pile of three cars.