Comments on: Freebore Boost Effects http://emptormaven.com/2007/03/freebore-boost-effects/ Oiling the Gears of Capitalism with Information Wed, 16 May 2012 18:33:55 +0000 hourly 1 http://wordpress.org/?v=3.3.2 By: Alexander_Degtyarev http://emptormaven.com/2007/03/freebore-boost-effects/comment-page-1/#comment-84423 Alexander_Degtyarev Wed, 23 Nov 2011 19:30:53 +0000 http://consumermaven.wordpress.com/2007/03/29/freebore-boost-effects/#comment-84423 Propellant loses energy in the process of heating up the can, energy it cannot spend on accellerating the bullet. The volume of the propellant is reduced when it contacts the cold can and cools off. A hot can doesn't cool the propellant nearly as much, and thus doesn't decrease the volume as much, which in turn leaves more energy for accelleration. Propellant loses energy in the process of heating up the can, energy it cannot spend on accellerating the bullet. The volume of the propellant is reduced when it contacts the cold can and cools off. A hot can doesn’t cool the propellant nearly as much, and thus doesn’t decrease the volume as much, which in turn leaves more energy for accelleration.

]]> By: EmptorMaven » Blog Archive » Shooting the Short-Barreled XCR http://emptormaven.com/2007/03/freebore-boost-effects/comment-page-1/#comment-2776 EmptorMaven » Blog Archive » Shooting the Short-Barreled XCR Tue, 20 Apr 2010 12:51:15 +0000 http://consumermaven.wordpress.com/2007/03/29/freebore-boost-effects/#comment-2776 [...] the silencer on increases muzzle velocity even further (thanks to an effect known as “freebore boost“): With the gas system off and the silencer on this gun shoots factory 55gr bullets over [...] [...] the silencer on increases muzzle velocity even further (thanks to an effect known as “freebore boost“): With the gas system off and the silencer on this gun shoots factory 55gr bullets over [...]

]]> By: federalist http://emptormaven.com/2007/03/freebore-boost-effects/comment-page-1/#comment-46 federalist Mon, 09 Apr 2007 04:03:59 +0000 http://consumermaven.wordpress.com/2007/03/29/freebore-boost-effects/#comment-46 Could air density alone explain this phenomenon? If my calculations are correct then air heated to 150F is 85% as dense as the standard atmosphere in which I was testing. (This is the same air density we would typically find at an altitude of 5500 feet.) But remember that I was taking the temperature of the exterior of the can, meaning that the propellant gases heating it from the inside must have been much hotter. If the air was still up around 400F by the time the next bullet went through then the air density would have been only 60% as dense, which seems like it could make a significant difference -- though only during the six inches the bullet was travelling through the suppressor. In principle we could try shooting at a higher altitudes to determine the effect of air density on muzzle velocity, independent of other phenomena -- perhaps on propellant burn -- present in a heated suppressor. Could air density alone explain this phenomenon? If my calculations are correct then air heated to 150F is 85% as dense as the standard atmosphere in which I was testing. (This is the same air density we would typically find at an altitude of 5500 feet.)

But remember that I was taking the temperature of the exterior of the can, meaning that the propellant gases heating it from the inside must have been much hotter. If the air was still up around 400F by the time the next bullet went through then the air density would have been only 60% as dense, which seems like it could make a significant difference — though only during the six inches the bullet was travelling through the suppressor.

In principle we could try shooting at a higher altitudes to determine the effect of air density on muzzle velocity, independent of other phenomena — perhaps on propellant burn — present in a heated suppressor.

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