Indoors it won’t matter much what you choose so don’t let the home defense possibility rule out some otherwise solid cans. They’re all essentially the same, sound wise, when you’re lighting off supersonic 5.56 inside a room. By they’re all the same, I mean they’re all going to be loud as hell. It’ll obviously be quieter than an unsuppressed rifle. Mostly you’ll be cutting dB levels down to below the “this causes me physical pain” level. The new hotness that’s already been mentioned here seems to be the HUXWRX Flow 5.56k flow through that’s already been mentioned. They were just awarded the FBI SWAT or HRT contract (I don’t remember if it was one or the other or both). That’s primarily an indoor mission.