A player on PG3 by the name of NIFN showed me this page:
http://www.imfdb.org/wiki/S.W.A.T._4
A quite detailed look at the weapons/tacaids in SWAT 4.
The thing that really caught my eye was this section:
http://www.imfdb.org/wiki/S.W.A.T._4#NPC-Only_Weapons
Seems there are a fair amount of weapons that are suspect NPC only, I'd love if we could use the small shotgun as an additional breaching tool. 
If only there were FPV models/reloading animations and so on for those weapons.. 
—
SAS_Master - Regimental Sergeant Major
GCHQ
"He's trusting you to do your job which is to clear that corner! Nothing else!"
I do believe i have such weapons, in the original half finished S4 mod
Lt_Col WIZ, VC, MiD (Ret)
This is why we can't have nice things
When the going gets tough, the tought get going.