The extended mag attachment for the Jackal is the only attachment left I need to find. I played the first three levels again, but nothing. All I find is the standard Jackal and the CQC Jackal, but the one with extended mags is nowhere to be found.
If I find this last attachment I'll get the trophy, so if you could help me out I'd always be in your debt. Thank you in advance.

I never double post or bump topics but I really really need some help here.