?  guess its a playing style qustion.... 
 
I play a ton of Hardcore HQ
 and use BLING  acog + silencer
 
my interest is b/c when equipped with a FAL, the enemy seems to take longer to pinpoint my location as compared to any sniper gun..why is that?

I would go with the FAL. Because the main purpose of the Intervention is accuracy and ACOG just decreases it a lot.

if your playing hardcore then FAL with acog for sure, other wise my favorite set up is  the 50 cal with an acog attached

FAL with Acog.

You know... I never liked the idea of silencers on Assault rifles, seems like a lame reason to weaken your gun.

I went through a MW2 phase where I used a FAL solely because it had one of my favorite reload animations.

How about ACR with Acog . best damn thing

Acog isn't that good anyways use the holo sight if anything 
don't use the Red dot FAL it isn't aligned right 
Intervention doesn't really benefit from any attachment other than thermal and that just hurts my eyes 

" Acog isn't that good anyways use the holo sight if anything don't use the Red dot FAL it isn't aligned right Intervention doesn't really benefit from any attachment other than thermal and that just hurts my eyes  "

FAL with ACOG

FAL, Shotgun Attachment, and ACOG/Holographic (it depends on the map really). That shotgun is no joke when it comes to Hardcore plus it stops the sway of the gun detail around the red dot when in iron sights.