I dunno I've seen some situations lately that I honestly wanna call possible cheating. I unloaded an entire storm bolter clip into a chaos marine that was locked into melee clangs the whole time. My shots registered hitting the friendly a few times but something like 40 shots did zero damage to the enemy player. I've seen lag and that was not lag.
Which you can still do. Just get your lock, unscope to get rid of the spread, kill. I think I got something like 15 AI kills with the lascannon the other night on Agnathio, not even really trying. It's just kind of a dumb mechanic IMO. The giant red beam painting your face is enough warning, and if you get shot in the back or because you're staring down your scope all the time, you deserved it. It's just a noob trap the way it works now, another unintuitive mechanic.
I go unscoped whenever I can so I can (try to) see when I'm about to get pegged, but I swear I've tried unscoped on people braced on railings and missed. So, do you actually have to scope, start firing, then unscope for it to work? Or is it just never 100%?
From what I've seen scoping to get the mouse over the target (i.e. cross hair turn red) is enough and you can unscope from that time
I had the exact same thing happen with a storm bolter. It feels like their cheating but they obviously aren't when other people damage them. Its such a weird bug.