1. Sound Signature Review 6.185 – Otter Creek Labs Infinity with subsonic 300 BLK. The Q mini Fix – an 8-in barrel proving ground, from the beginning. How does the versatile Infinity handle subsonic ammunition combustion out of a relatively short barrel? How does its performance compare with some older designs and some purpose-built 300 BLK designs? Can it hang? Introductory discussion for this technical paper published today.