Unlocking the new Gol Magnum in BF4 is just pure chaos, I ended up getting so frustrated I placed a spawn beacon just outside of the tower on Fire Storm and was dropping on the snipers that had taken the tower over. Took me several tries to master this strategy, but I got pretty good at hip firing the sniper rifle (silencer helps too, the others don't know its coming). Ended up unlocking the Gol Magnum, the SRR-61 and Sniper Service Star all at the same time. Now that I have the SRR-61 I doubt I will ever use the Gol Magnum ever.
I just went through this hell for reasons I don't even know, because I never play Recon.
Got lucky when I found 2 guys on the tower that were launching missiles, so I just climbed up, walked up to them, and gave them a close up headshot. Then I won a medium range (150m or so) sniper war for the 3rd kill, figured out I could shoot through the floor grating on the tower for the 4th kill, and then got a guy on the oil platform nearby for the 5th kill.
What a nightmare. Sniping in this game is so awful.