Thread: Indoor range

Question for those with a scientific mind. Could probably find on the net but probably quicker here. A friend is looking at building an indoor range off a 100yrds to mitigate noise. He has out door ranges already. We've looked at concrete pipes and ppe etc but very expensive. also containers end to end but transport kills them. My question is that when a bullet breaks the sound barrier how long/far does that shock wave of noise travel? In other words could you say maybe use two or three containers as baffles with baffles inside like a giant suppressor with a small opening on the last. Would that contain the sonic boom and the bullet could then travel on happily to the target with little more than a muffled sound? Or would you have to have it contained all the way? We can bury containers or what we use to make that side of it very sound proof.
Interested in what you guys think or have done