I got my expert explosives at my first try on Karkand.
I was going for my veteran because I thought I would never make it to the expert explosives.
You need a lot of luck if you aren't using the jihadbomber tactics.
The most luck I had was that someone just spawned at the Hotel before we took it back and I my 37th C4 kill with just 4 tickets left and I ended the round with vet/exp explosives and a good KDR.
(I've got a screenshot but I am at work now and the site was sort off down yesterday)

This week I also got some SF badges Support and Special Ops (will try to get the engineer,AT and medic today).
Some other luck I got was that I joined a server at Warlord and our team only had 1 flag at the palace.
I picked up a medic kit and I was throwing medic bags around the room and got my 10 heal points for the veteran First Aid Badge.

So I hope I can get all the veterans of all special forces kits today.