The weapon pack that CSi. is using is FAS:2 here is the link to the workshop collection:
https://steamcommunity.com/sharedfiles/filedetails/?id=258192021
+1: haven't got to play with you yet, but as far as I've seen you're a pretty pretty cool guy, getting a little annoyed with you killing me when i'm at bounty, but over all pretty chill dude.
How To Fix Missing Map:
hey i'm not sure if you've fixed it yet or not but there are a few ways you can go about fixing it:
you can allow custom content from all servers, the way you do this is by going into options/multiplayer then press the drop down menu
Another way you can fix it is by subscribing to the workshop map : https://steamcommunity.com/sharedfiles/filedetails/?id=2028581413&searchtext=southside
The final way you can fix it is by extracting the map and putting it in garrys mod root folder for maps yourself: steam\steamapps\common\GarrysMod\garrysmod\maps
I hope this helped you in some sort of way..