Buck13
Member
I find the pressure/velocity data and the talk of flame cutting and hot guns with Lil'Gun perplexing and fascinating.
On the one hand, the high velocities at low pressures seem to suggest that it has burn characteristics that are unusual: that it somehow comes up to a moderate pressure and continues burning at that pressure for a long time, generating a lower but wider pressure curve over time. Since this means the pressure DOESN'T rise too quickly to raise pressure before the bullet moves much, but DOES continue burning well for a long time as the bullet moves down the barrel and the volume behind it increases, does that mean it burns more slowly yet more persistently than other slow magnum pistol powders like H110, AA#9, 2400, and 4227?
But then why does it have a reputation for flame cutting and statements that it makes someone's gun hotter after a few shots than other powders. These claims seem to be relative even to the true magnum powders named above. My naive physics says that hotter gases have higher pressure (for the same amount of gas, which seems like it should come from the same amount of powder, more or less) and that expansion (as the bullet moves along) should cool the gas, and my naive chemistry says that higher temps should speed the burning, yet Lil'Gun seems to be able to be very hot, yet burning slowly, yet burning well over more time than other powders.
I guess that a very slow burn at a high temp, producing less pressure at any instant due to less gas but transferring MORE heat due to a longer burn time at that temperature, and producing high velocity by sustaining the pressure curve much farther to the right as the bullet accelerates (apparently all Cartesian test guns are aimed to your right!) could explain this.
Am I on the right track in this thinking? Has anyone seen actual piezo plots of pressure vs time for these powders that would show a uniquely broad but low peak for Lil'Gun?
On the one hand, the high velocities at low pressures seem to suggest that it has burn characteristics that are unusual: that it somehow comes up to a moderate pressure and continues burning at that pressure for a long time, generating a lower but wider pressure curve over time. Since this means the pressure DOESN'T rise too quickly to raise pressure before the bullet moves much, but DOES continue burning well for a long time as the bullet moves down the barrel and the volume behind it increases, does that mean it burns more slowly yet more persistently than other slow magnum pistol powders like H110, AA#9, 2400, and 4227?
But then why does it have a reputation for flame cutting and statements that it makes someone's gun hotter after a few shots than other powders. These claims seem to be relative even to the true magnum powders named above. My naive physics says that hotter gases have higher pressure (for the same amount of gas, which seems like it should come from the same amount of powder, more or less) and that expansion (as the bullet moves along) should cool the gas, and my naive chemistry says that higher temps should speed the burning, yet Lil'Gun seems to be able to be very hot, yet burning slowly, yet burning well over more time than other powders.
I guess that a very slow burn at a high temp, producing less pressure at any instant due to less gas but transferring MORE heat due to a longer burn time at that temperature, and producing high velocity by sustaining the pressure curve much farther to the right as the bullet accelerates (apparently all Cartesian test guns are aimed to your right!) could explain this.
Am I on the right track in this thinking? Has anyone seen actual piezo plots of pressure vs time for these powders that would show a uniquely broad but low peak for Lil'Gun?
