New here, Suppressed T/C Contender???

[Killzoneq2]

I recently received my Tac16 Suppressor from Tactical Innovations for my full auto Colt AR-15 .223. and y T/C Contender.223. I love the supperession that it provides. I will be shooting my Contender mostly and it has a 22" barrel on it threaded for the Suppressor. It is quiet but I want it more quiet!! How and where can I purchase 300 Whisper ammo? Will my T/C Barrel work with it? I am no reloader, never done it, I just want to purchase some subsonic rounds to play around with my Contender.