Jeez. Once I hit 40 I realized that the best gun in the game is P90 with double tap. But I rarely use it anymore cuz all I do is go for challenges. It takes so long to rank up without getting challenges done, so I'm just switching my classes constantly once I get some marksman challenges with whatever gun. One more level til the barret... ;)
I don't see the point in martyrdom. To me its just a cheap way to get kills. It's like inviting people to suck at this game. You can kill me, i'll just drop a grenade at my feet it's so stupid.