>>327309158
These stats don't really mean much unless you're playing the same grinder on the same gamemode every time and I'm assuming you're playing different grinders because those stats are wildly inconsistent otherwise. Some are simply better at securing kills because they're heavy hitting or flexible enough to dive in but there's still some chance to how the match plays out. Your own comfort and skill with each playstyle comes into it too. It's not random but it is hard to predict.

If you really want killing blows the best way to get them is to get into the action quickly and try to make the most of each of your shots. Unless you're at long range, hold them until you can hit the torso or any spots missing armor plates. If you've got the speed or the enemy is open, get behind them and focus all of your fire on their rear weak spot. If an enemy is turning it might be better to wait rather than dump all of your damage into an armored limb.