SUBSONIC ROUNDS WITH SUPPRESSOR CRACK

Your chrono cannot tell you whether your bullets are subsonic. And the magnitude of the wave form drag increases as the local regions of supersonic flow spread over more of the bullet, peaking only once the bullet is entirely supersonic. Where the drag curve first starts to climb marks the critical Mach number. In fact, it is the introduction of that вЂwave form dragвЂ™ that is responsible for the huge increase in the drag, which starts BEFORE the bullet reaches the speed of sound. This is because the creation of the supersonic shockwave introduces a whole new form of drag, вЂwave form drag,вЂ™ that doesnвЂ™t exist when the bullet is entirely subsonic.

Notice that up until about 0.8 Mach, the drag curve is more or less flat, then it suddenly rockets skyward. Exactly where it will begin varies according to bullet design but Paulson ballparks it at 0.8 Mach.ДЇor supporting evidence, look at the ballistic coefficient tables for any bullet, such as this one. Paulson, widely regarded as the dean of suppressors ( ), showed that a bullet traveling as little as 8/10ths of the speed of sound can have entered the transonic region and begun producing a supersonic crack. They ALWAYS are separated by the transonic velocities. Point of fact, for any object that produces drag, the subsonic and supersonic regions never meet.

SUBSONIC ROUNDS WITH SUPPRESSOR CRACK

And since it is the air - and not the bullet - that causes the supersonic crack, that crack already will have begun, despite the fact that the bullet has not yet reached the speed of sound. The velocity at which this first occurs is called the вЂcritical Mach number.вЂ™ From that velocity and faster, until the object has shed the last remnants of its localized subsonic flow, it is neither subsonic nor supersonic, it is TRANsonic. The object itself is yet below the speed of sound, but some of the air surrounding it - in its haste to get out of the objectвЂ™s path - has exceeded the speed of sound. So if you were to accelerate a jet (or load cartridges incrementally hotter) until reaching the speed of sound, before crossing the вЂњsound barrier,вЂќ some of the air it was pushing aside would HAVE TO have been accelerated to the speed of sound, resulting in localized supersonic flow. Supersonic means there is ONLY supersonic flow NO localized subsonic anywhere on the object. Transonic means there is _some_ localized supersonic flow but also _some_ subsonic flow. Subsonic means there is NO localized sonic or supersonic airflow, anywhere on the object. Relative to sound, there are three regions of velocity: subsonic, transonic, and supersonic. the sound coming from the gun.ДЄlthough the following video was just meant to be chronograph testing of the American Eagle вЂњSuppressorвЂќ ammo, itвЂ™s queued up here to start at a similar subsonic/supersonic audio test:ДЄ chronograph cannot determine whether a bullet is subsonic. The echo and the crack follow the bullet.

You can hear the sonic boom travel downrange.

This becomes extremely apparent when you take the exact same round and find that itвЂ™s supersonic in your 7.72вЂі bbl CZ Scorpion Evo and subsonic through a 4.5вЂі bbl pistol. However, many calibers and brands of ammo achieve subsonic velocity by simply using a heavier projectile that doesnвЂ™t go as fast even with the same power and pressure behind it. 22 LR brands - that subsonic ammo and supersonic ammo are loaded to entirely different power specs.

It is true in many cases - for example.

While the sub/super difference is massive in the 597, both ammo brands stay subsonic in the short pistol barrel and the two are completely indistinguishable from each other. 22 LR rifle is fired through the Walther PPQ.

In the video, the exact same ammo shot through the Remington 597 HB.

In real life, the difference is even more pronounced than in the video.ДЄs I have seen many comments on other videos and elsewhere online suggesting that the difference is actually due mostly to the higher power and pressure of supersonic loads: In a lot of calibers itвЂ™s actually uncomfortable to shoot supersonic ammo without ear protection, whereas a subsonic load with the same powder charge can be barely noisier than the sound of the action cycling. While my camera in this configuration wonвЂ™t dampen or scale down audio after a volume spike, the sonic boom absolutely maxes it out. The truth is microphones on cell phones and videos cameras max out between 90 and 110 dB.

Subsonic rounds with suppressor