I just notice that the stats of RPK are not shown in WEAPON STATS on the player page.
Is the amount if kills with that weapon below 100?
Umm nope. I have 1039 kills with RPK and it doesn't show up. I also checked other people's player profile to make sure this case. The same thing happens to atlaslion923 (https://bf4db.com/player/337373603) who has 63282 kills with RPK.
That's when I think that this is a common bug so I report it.
Ah okidoki :) Thx for reporting!