There is a bug with all weapons that can let you reload a full/near full clip and not need the full ammo cost. Example: I have 0-120 with SMG, I reload and have 30-96. 6 free shots out of nowhere. This bug doesn't affect everyone, but I know it's not just me. The bug is NOT caused by lag, someone with 100 more ping than me was unaffected while I had the bug.
How to reproduce: Empty your clip. Reload. Check how much ammo you have left. If it's more than 10-40 / 30-90 /
6-42 then it's bugged.