Some time ago I saw a gif from someone with what looked like a Japanese username. It was a gif of the spear doing 1-shot kills on bile titans and it had little lines showing how to line up the dot and the triangle relative to the launcher muzzle to hit the titan in the head.
I can’t find it now. Does anyone know where to find it? Frankly I think it was buried in a reddit comment thread but I just lurk over there these days.
Edit: found it, it’s https://www.reddit.com/r/Helldivers/comments/1cu0ewh/comment/l4fggwq/ or https://imgur.com/a/ptvdcvf which is too large to post directly.
Pretty sure you just need to be directly in front of your target with the spear to hit the head. Don’t think I’ve seen the gif though.