Explosives Expert #2 Challenge only counts frag grenades

I might add that since the 3rd Explosives Expert Challenge is described as:

"Get kills in a match using explosives." [30 required]

... I would also be concerned that only frag grenades count for that, too.
Arguably, getting 30 kills IAR with frag grenades is virtually impossible in any standard game mode (i.e., excluding Portal).

Today I also confirmed that getting a multi-kill via a red exploding barrel also does not count towards these challenges.

Honestly what a joke these challenges are. They need to be fixed. I too was using C4 on tanks and got a few multi kills with them only to find that it didnt count towards the challenge. You’re telling me frags are the only explosive that can be used for the challenge? 
 
Ridiculous if you ask me. I was trying the squad deathmatch one too where you need to get 30 revives in one match. Virtually impossible with the instant respond, no one hangs around for a revive. 

As of the 1.1.1.0 patch, I was finally able to complete this Challenge (and also the 3rd requiring 30 kills in a round) as the gunner of an IFV equipped with the grenade launcher turret. 

So the explosives of the IFV grenade launcher gunner count towards this. I'm not sure if that's always been the case, or if the general issue of certain explosives not qualifying has been resolved.

Yeah, can also confirm, getting a tank kill that is loaded with players doesn't count when using any of the mines. The "Get multi-kills of two or more by using explosives." should just be renamed "Get multi-kills of two or more by using grenades." since that seems to be only thing that works.