308 Whisper ammunition along with standard 9mm and 40 caliber ammunition. For my recording session that day I used 300 AAC Blackout (7.62×35mm) and Remington. These are designed from the start as dedicated subsonic projectile systems. Specialized firearms and ammunition may be used to optimize total subsonic ammunition effectiveness. 45 ACP ammunition load, of a 230 grain bullet, is subsonic. For example, the traditional military standard. Some ammunition types were inherently designed with heavier, slower standard bullet weights and velocities. Subsonic ammunition with normal bullet weights often fails to properly function in such firearms. For these ammunition loads, balancing bullet weight and velocity are required to ensure that the ammunition will still reliably cycle semi-automatic firearms. Subsonic loads for 9mm commonly use 147 grain (9.5 gram) bullets at velocities of 990 ft/sec (300 m/s). The very common 9×19mm Parabellum standard military round is a 115 grain (7.5 gram) bullet at velocities typically around 1,300 ft/sec (400 m/s). Some subsonic ammunition is used in non-suppressed firearms to gain the advantages of heavier bullet weights.įor standard rounds, heavier bullets are loaded in standard ammunition, which reduces muzzle velocity below the speed of sound. Subsonic ammunition usually uses heavier bullets to retain as much energy and momentum as possible at the lower velocities. For suppressed or silenced firearms, this supersonic bullet sound would significantly add to total sound level. Subsonic ammunition is ammunition designed to operate at speeds less than the speed of sound, which avoids the bullet making a supersonic shockwave or “crack” as it travels through the air. Here is some information about bullets and suppressors: No worries, this is normal… (funny factoid) You may notice the sound of the muzzle happening way after the bullet pass by. There was some echo coming back off the mountain but it is minimal. The locations is a wide open field with a mountain/forest backdrop. The microphones were placed 1050 Feet (ft) 320.04 Meters (m) 350 Yards (yd) away from the shot position. The bullet has slowed a bit by the time it passes the microphone. Keep in mind that the feet per second calculation is from the muzzle, not down range. 308 Win 200gr traveling at approximately 1040fps. 308 Win 180gr traveling at approximately 2570fps. I love it when that happens!īelow is a audio demonstration of supersonic and subsonic bullets shot from a Remington 700 Rifle with a Gemtech (Caliber: 7.62mm NATO /. I was able to acquire some final material that will be in the new library. The first two were just for testing and scouting the various locations on this massive piece of North Idaho real estate that I call my second home. I have ventured out to my favorite recording location on three occasions in the last month. Since I’m diving into unknown territory with these higher calibers and longer distances I’m basically just going out into the field and making a somewhat educated guess as to how and where to record these little slugs of metal as they zip and bounce by the microphones. To get the perfect bullet pass by or ricochet you have to calculate speed of sound, bullet velocity, grain size, powder loads and weapon type. Creative Sound Design, LLC accepts no liability for the consequences of any actions taken on the basis of the information provided in this blog post. This blog post is for educational purposes only. We used 2-way radios to communicate and I was notified before each shot that one was “Coming down range” and after the shot “All clear” We were in an area where we could safely record these knowing that when a bullet ricochet sent the bullet off into the distance that there was ample room for the bullet to land without endangering any person or property. I was protected and at a safe distance at all times. Because of the distance we were shooting I was downrange in the area where the bullets were impacting and passing by. This type of sound recording is not for the faint of heart. This recording adventure is not easy and I will say it’s been one heck of a learning curve.ĭo NOT try this at home. This time I’m going with larger calibers and shooting longer distances. After a year and a half of studying ammunition ballistics and acquiring all kinds of high speed and sub sonic ammunition, the recording of the second installment of Bullets HD Professional SFX library is underway.
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