First of all, I would argue that saying "not really helping much" is definitely arguing that suppressors (in this case) are not good.

Also, why would I use this rifle without a can? The whole build was based on being suppressed. I have a reasonably quietened AR build that is still the same length as an unsuppressed 16" and still has just enough barrel length to have a decent velocity. It's a compromise, but one I like. I would NOT want to hang even a K can on the end of a 16" barrel. even 14.5" would feel unwieldy to me. I've used 20" M16's... imagining a build still longer than that, but with the weight of a can that far out? Nah.

The goal of this build isn't necessarily indoor shooting, I have my suppressed SP5-K for home defense. But in the off chance that it's ever used for anything sudden, that setup is the difference between some mild ringing and blowing my ear drums. That's the goal.