1. Sound Signature Review 6.194 – Dillon Rifle Company DRC556 on the 14.5 5.56 M4. Oh my goodness – more Purposely Induced Porosity silencers? Yes. PIP is proliferating. How does this adaptation of the technology perform? Form factor is becoming a hot topic lately. Let’s explore this new silencer from Dillon in this introductory discussion to the whitepaper published today!