Ok so ive tried the FMJ and when ever i use it, and i get a kill it doesnt count. So far i have i think 2 FMJ kills to get the extended mag.. so whats the trick of getting the FMJ kills??

You made the same mistake I did. You have to kill somebody having the bullet go through something. So it only counts if the guy is behind a material and your bullets are able to penetrate that material and kill him.

Kinda lame because it makes getting the Mastery Challenge hard because this one is so hard.

ohhh ok thanks.. ya getting that mastery for the guns is gonna be a big pain

Yep...but trust me...it's worth the extra 10,000's of points .

I just did it for M4...working on 1000 kills now and then moving on to FAL

I'm working on the M4 and have like 10/40.

Yeah, FMJ is the slowest..but keep at it. It'll come =)

If I did it...so can you.

Yeah, I'll get it eventually. Just annoying since I used the M4 from level 1 all the way to level 20ish rather consistently (and did complete everything but FMJ [excluding marksman and expert, ofc]) so I want to branch out and use other guns more often.