Unlocking the MTAR-21 in Battlefield 4 is easier than it looks as you glance at the requirements, and IMHO its worth the tasks required for the unlock. You can find the Multi Talent Assignment in your BF4 Battlelog under Assignments, its the second to the last Silver Assignment.
Here’s what you need to get the MTAR-21:
Reach rank 10
Play China Rising
Get a kill with a sniper rifle in a round
Get a kill with an assault rifle in a round
Get a kill with an LMG in a round
Get a kill with a hand grenade in a round
The most difficult part is keeping track of what you need to do. So write it down, or bring BattleLog up on your PC, Tablet or Smart Phone or whatever helps you remember. There’s no need for you to get 3 of the 4 kills and then not get the 4th because you can’t remember what it was. I decided to try this on Operation Locker, and to be quite frank, I got lucky with 2 of the 4 kills. I didn’t record the actual gameplay where I unlocked the MTAR-21, the video below will show you the kills for this Assigment and its PDW reward, but that video was a test to see if I could get it as art of the accidental early release which turned out to be for the PC only. As a PS4 gamer, I didn’t get the MTAR-21 during this accidental early release, but the kills you see will earn you the MTAR-21 now. With all that being said, ignore any info about unlocking this weapon besides the actual kills that are required.
To do the unlock in the most frustration-free way I think I’d try a Conquest Large game on Operation Locker. Try any map you prefer, Operaton Locker is just a suggestion. Also, to be sure you get a full round of Operation Locker you might want to go into your Server Browser and search for a game on Golmud Railway because Operation Locker is after that in the default BF4 Server Map Rotation Cycle.
I’d start with the Sniper Rifle kill first, that way you don’t get the other 3 kills and get stuck on the last one. As far as grenade kills you can go with whichever grenade you are comfortable with but, I use the V40 Mini because I get 3 of them.
Youtube Video: Unlock MTAR-21