I am level 21 and have not been able to unlock a suppreasor for my Grendel

What am I doing wrong? Back at level 18 I unlocked it used it for three matches and the server kicked me and I lost it since it does not save.

Any idea ~ I really like it and would like to use it

Thanks in advance

Painbringer71

Had the same problem youre gonna need another weapon attachment unlock

IS there FAQ on how the heck these unlocks work? I have multiple characters ( i play them all) and have never had a a suppressor unlock available except the time I mention above that was robbed from my grasp