yeah ... you see 2 or 3 people standing 50 feet away and neither has a clue you're there... send like 20 balls to them. You'd get them out, guaranteed. (and if done right they still wont know where you were)
If you want to do the osok thing still, I think the only way you can be truly safe from being detected is when you're working with a larger force, and there is a battle or fighting going on that distracts and causes enough noise for you to move and fire without being noticed. As long as your sound is masked or the other team is not directly concerned with finding you, you should be fine.