Forum:Reticle help

I have been trying to unlock the final EOTech recticle by getting bloodthirsty medals. I have gotten 9 of 10 and now I can not, for the life of me, get my final bloodthirsty medal. I have gotten bloodthirsty medals with my EOTech sight on and I have been aiming down the sights for all 5 of the kills but it will not count it towards my challange. Has anyone else had this problem or know what I am doing wrong? Like I have already gotten 9 of them but now that I am on my last one, every time i get a bloodthirsty medal it doesnt count it even though I am aiming down my sights and got all 5 kills while aiming down my sights, please help, its driving me crazy!