jstein650
Member
I know, not again, but I was thinkin' - I wish I wasn't, but hey, that's part of the fun of this forum. A while back the ubiquitous subject again came up, and some lively discussion followed. I posited that the only significant factors with regard to recoil were: the mass of the firearm, the mass of the projectile, the mass of the propellant, and the muzzle velocity of said combined ejecta. This led to the path of reasoning the definition of the objective 'free recoil energy' and the subjective 'felt recoil' debate. At any rate, inevitably, the idea of chamber pressure emerged, with the reasoning being that a faster powder will produce a higher chamber pressure, whose action upon the bolt face will necessarily result in a higher linear force upon the shooter. I argued that while that may be true, the time that it is exerted will be for a shorter period of time and that should obviate any difference in 'felt recoil'.
After reading a few posts on subjects touching the same question, it occurred to me that chamber pressure itself has nothing to do with recoil actually. In the same way I can hold a fully charged scuba tank. Nothing happens. The pressure in a gun chamber is acting equally on all sides, including the base of the bullet on the opposite end of the bolt face. The exterior world (the guy holding the gun) doesn't know anything until that projectile begins to move, and is pushed in the opposite direction, due to inertia.
With regard to understanding powder burn rate, most folks agree that in most all cartridges, the powder is pretty much 'consumed' before the projectile moves more than a even an inch, yet there are significant disparities when it comes to velocity in even the shortest barrels, the slowest powders always giving the highest MV's. Of course, with current powders, it always takes more of a slow powder to attain or surpass the max vel. you can get with a faster powder. Both powders will be able to hit the pressure ceiling, but the slower can hold it there for a bit longer. After the initial ignition, there will be a perhaps slight, but significantly longer duration for which that powder is still exerting an increasing amount of force on the the bullet (in an EXPANDING combustion chamber VOLUME, no less) and that will get you a higher MV. The drawback, if you will, is that propellant mass is always given a 25 to 50% increase in recoil figures since it always exceeds the speed of the projectile when firing.
Bottom line: We're not getting anywhere a linear constant acceleration from modern handguns, shotguns, or rifles throughout of the length of their barrels, so the slower powder=softer recoil does not really make sense.
After reading a few posts on subjects touching the same question, it occurred to me that chamber pressure itself has nothing to do with recoil actually. In the same way I can hold a fully charged scuba tank. Nothing happens. The pressure in a gun chamber is acting equally on all sides, including the base of the bullet on the opposite end of the bolt face. The exterior world (the guy holding the gun) doesn't know anything until that projectile begins to move, and is pushed in the opposite direction, due to inertia.
With regard to understanding powder burn rate, most folks agree that in most all cartridges, the powder is pretty much 'consumed' before the projectile moves more than a even an inch, yet there are significant disparities when it comes to velocity in even the shortest barrels, the slowest powders always giving the highest MV's. Of course, with current powders, it always takes more of a slow powder to attain or surpass the max vel. you can get with a faster powder. Both powders will be able to hit the pressure ceiling, but the slower can hold it there for a bit longer. After the initial ignition, there will be a perhaps slight, but significantly longer duration for which that powder is still exerting an increasing amount of force on the the bullet (in an EXPANDING combustion chamber VOLUME, no less) and that will get you a higher MV. The drawback, if you will, is that propellant mass is always given a 25 to 50% increase in recoil figures since it always exceeds the speed of the projectile when firing.
Bottom line: We're not getting anywhere a linear constant acceleration from modern handguns, shotguns, or rifles throughout of the length of their barrels, so the slower powder=softer recoil does not really make sense.