Quietest Bullet Supersonic crack What determines it?

How Loud is the sonic boom from a bullet? Not only that, but how loud is the sonic boom from different shaped bullets?

We have long very aerodynamic bullets, we have somewhat long flat nose hollow point bullets, we have short round nose bullets, different diameter bullets

Our Setup for this test is going to be fairly simple, we don’t need a lot of gear we just have to be accurate with our shots and you’ll see why that’s important in a moment. For the gear we need we are going to need several rifles, different calibers and different shaped bullets, and we will need the sound meter. We are also going to have the Chronograph setup to measure the bullet speed as well.

We will be shooting suppressed so we keep the initial sound dB level low so it won’t affect the sound from the sonic crack of the bullets downrange. How do we know that the gunshot from the muzzle is not affecting our measurement downrange? It’s because of something called the inverse square law, The inverse square law states that each doubling of distance the sound diminishes in Decibels 6 db so at 30 yards the sound from the muzzle blast would only be around 117 db. Inverse Square law: p2=p1×(d2/d1)
We are going to place the Sound meter 30 yards downrange and we are going to treat the test the same way we would if we were sound metering at the muzzle. When we sound meter test at the muzzle we have the sound meter 1.6m off the ground and 1m left of the muzzle so the bullet exiting is 1m from the sound meter traveling perpendicular to the meter. So for this test we are going to do the same thing, set the sound meter 1.6m off the ground and we will be shooting the bullets past the sound meter at 1m left of it, the difference being the sound meter is 30 yards downrange so the peak sound capture we record will be the sonic crack of the bullets passing by. To make sure the bullets are going past in the same spot we will have a paper target downrange to aim at.