Using subsonic bullets also causes a greater risk of jamming, which in a firefight could mean the difference between life and death. Likewise, a bullet can't be too light or too heavy, because too much in either direction can prevent the bullet from obturating. The melted leading can be a pain in the ass to remove, and can permanently damage the weapon unless it's cleaned. In technical jargon, the failure of a clean "burn" and the resulting lowered accuracy and range is called a failure of "obturation." Normally, a bullet expands - or obturates - to the size of its barrel after being fired, keeping the bullet on target and preventing the gases that propel it from rushing past and melting to the inside of the gun. makes it hard to get a clean burn of the propellant causing rapid fouling of the weapon." This results in bullet that is far and away less accurate, doesn't go nearly as far, and "creates lower pressures which. According to the solicitation, subsonic bullets "experience significant accuracy problems due to excessive deviations in velocity." The gunpowder (or propellant charge) for a subsonic bullet has to be used in smaller quantities than for a normal bullet, and the bullet itself has to be heavier. Breaking the sound barrier also pretty much negates the use of a sound suppressor, or "silencer," which the special forces would likely want to use against militants in Afghanistan and around the world.įor one, to keep a bullet from breaking the sound barrier - 1,100 feet per second at sea level - requires several trade-offs at higher calibers. 338 calibers, the bullets will travel at low enough velocities to avoid breaking the sound barrier, thus creating no "crack" noise. In theory, and for rifles in the 5.56, 7.62 and. The reason, according to the solicitation, is to " provide superior covert and stealth capabilities" for not only the military, but police forces and the Department of Homeland Security. In its latest round of small-business solicitations, the Pentagon's Special Operations Command, or SOCOM, is seeking out subsonic ammunition. Now the commandos want to be sneakier with slower, quieter bullets. But it does keep up the comparative accuracy to 200 metres and even 300 metres in ideal conditions.Most bullets make small sonic booms when flying through the air, which to our ears sound like a loud, distinct " crack!" For the Pentagon's special forces, that makes it hard to be sneaky about what they're shooting. The addition of a string/ribbon tail to the ball helps the ball transit the transonic zone (as does the Nessler ball) at the cost of extra drag.
My 10 bore musket will do well at 100 metres with 124 grains but develops a mind of it's own before 200 metres. One of the reasons why smooth bores run out of accuracy well before they run out of range. In particular he looks at just this question (and many other valuable ballistic things for smooth bores etc) and clearly shows that the transonic area is where great instability occurs and you either want to be well below it or well above it for consistent flight.
His findings on spherical ball obturation is something I have never seen found before though OT and probably shows up my ignorance.
ARE SUBSONIC ROUNDS MOST ACCURATE DOWNLOAD
Download Dr David Miller's doctoral thesis on the 17th century matchlock's internal and external ballistics (public document) via.
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