One of the factors I am looking for, when selecting loads for my revolvers, is listed pressure. When taking handgun while hunting, if in a hurry, the last things I have on my mind are earmuffs and/or plugs. In that respect, I prefer loads (for 44 Magnum now, and hopefully 45 Colt later) that are giving moderate muzzle blast, let say no more than from 30-06 rifle.
Seems to me that a general opinion is that less peak pressure (as listed in manuals) gives consequently less muzzle blast. In other words, starting loads for revolver at 18 to 23 kpsi should give less muzzle blast than maximum loads creating 36 to 38 kpsi.
Is that statement too general? What about smaller amount of fast burning powder that has a high listed pressure? Should we expect in some instances, due the higher expansion ratio in barrels like 6-6.5”, less muzzle blast than from loads with higher amount of slow burning powder, but less listed pressure?
When talking about "low" and "high" pressures that are results of starting and maximum loads, listed in some reloading manuals.
However, if I have it right, we are talking about the peak pressures in cylinders, and I am not sure about their effect on blast level on the muzzle. My point is that, due the expansion ratio in cylinder and barrel, smaller amount of fast burning powder, that has high starting pressure, might have lower muzzle pressure, and consequently lower muzzle blast, than load with larger amount of slow burning powder, with less starting pressure.
I searched internet and the best and simplest explanation I could find is this:
Internal Ballistics of Muzzleloaders https://www.celnav.de/muzzleloaders/internal_ballistics.htm
Generally, a fast-burning powder is more energy-efficient than a slow powder because it burns more completely during the residence time of the projectile in the barrel. This results in a lower residual gas pressure at the instant the projectile exits the muzzle. So, why should anyone want to use a slow powder at all? Because of the lower peak pressure! A heavy charge of fast-burning powder behind a heavy long projectile might develop a peak pressure exceeding the upper limit set by the gun manufacturer. Too high a peak pressure may further show itself by torn patches and reduced precision. While generally 3FG powder is a good choice for handguns and small- or medium-caliber (≤ .50) rifles firing round balls, the slower 2FG powder is better suited for rifles firing heavier long projectiles (except the smallest calibers). It is also better for big-bore (> .50) rifles firing heavy round balls (see below).
Although, this is about muzzleloaders and black powder, but the principle should be same for fast and slow burning smokeless powders.
I searched internet and there is nothing about muzzle pressure and muzzle blast for different loads. However, here are some data, but just for standard cartridges and firearms, assuming as per SAAMI specifications.
Gunfire Noise Level Reference Chart https://earinc.com/gunfire-noise-level-reference-chart/
In addition to the blast from the muzzle, when talking about revolvers, question is how much blast is generated due the gap between cylinder and aft side of barrel? I would say that should be quite difference in a blast from ordinary revolver with gap .006-.008”, from the gap like .002”, or even less, as on FA revolvers.
Talking about different powders and their loads, I checked on Hodgdon reloading website https://www.hodgdonreloading.com/reloading-data-center?rdc=true&type=53 , and found two interesting loads that could be compared:
Revolver: 44 Magnum, barrel 8.275”, bullet 325 GR. BTB LFN GC, starting loads:
Load 1: Powder IMR 4227, 17.0 grains, 1041 fps, 19 200 CUP
Load 2: Powder Winchester 231, 9.0 grains, 1035 fps, 32 100 CUP
The bottom line is; which load, using the same bullet, fired from the same revolver, with almost the same velocities, will give us less muzzle blast?
I hope that somebody knows more about this subject and could tell us from personal experience.
Seems to me that a general opinion is that less peak pressure (as listed in manuals) gives consequently less muzzle blast. In other words, starting loads for revolver at 18 to 23 kpsi should give less muzzle blast than maximum loads creating 36 to 38 kpsi.
Is that statement too general? What about smaller amount of fast burning powder that has a high listed pressure? Should we expect in some instances, due the higher expansion ratio in barrels like 6-6.5”, less muzzle blast than from loads with higher amount of slow burning powder, but less listed pressure?
When talking about "low" and "high" pressures that are results of starting and maximum loads, listed in some reloading manuals.
However, if I have it right, we are talking about the peak pressures in cylinders, and I am not sure about their effect on blast level on the muzzle. My point is that, due the expansion ratio in cylinder and barrel, smaller amount of fast burning powder, that has high starting pressure, might have lower muzzle pressure, and consequently lower muzzle blast, than load with larger amount of slow burning powder, with less starting pressure.
I searched internet and the best and simplest explanation I could find is this:
Internal Ballistics of Muzzleloaders https://www.celnav.de/muzzleloaders/internal_ballistics.htm
Generally, a fast-burning powder is more energy-efficient than a slow powder because it burns more completely during the residence time of the projectile in the barrel. This results in a lower residual gas pressure at the instant the projectile exits the muzzle. So, why should anyone want to use a slow powder at all? Because of the lower peak pressure! A heavy charge of fast-burning powder behind a heavy long projectile might develop a peak pressure exceeding the upper limit set by the gun manufacturer. Too high a peak pressure may further show itself by torn patches and reduced precision. While generally 3FG powder is a good choice for handguns and small- or medium-caliber (≤ .50) rifles firing round balls, the slower 2FG powder is better suited for rifles firing heavier long projectiles (except the smallest calibers). It is also better for big-bore (> .50) rifles firing heavy round balls (see below).
Although, this is about muzzleloaders and black powder, but the principle should be same for fast and slow burning smokeless powders.
I searched internet and there is nothing about muzzle pressure and muzzle blast for different loads. However, here are some data, but just for standard cartridges and firearms, assuming as per SAAMI specifications.
Gunfire Noise Level Reference Chart https://earinc.com/gunfire-noise-level-reference-chart/
In addition to the blast from the muzzle, when talking about revolvers, question is how much blast is generated due the gap between cylinder and aft side of barrel? I would say that should be quite difference in a blast from ordinary revolver with gap .006-.008”, from the gap like .002”, or even less, as on FA revolvers.
Talking about different powders and their loads, I checked on Hodgdon reloading website https://www.hodgdonreloading.com/reloading-data-center?rdc=true&type=53 , and found two interesting loads that could be compared:
Revolver: 44 Magnum, barrel 8.275”, bullet 325 GR. BTB LFN GC, starting loads:
Load 1: Powder IMR 4227, 17.0 grains, 1041 fps, 19 200 CUP
Load 2: Powder Winchester 231, 9.0 grains, 1035 fps, 32 100 CUP
The bottom line is; which load, using the same bullet, fired from the same revolver, with almost the same velocities, will give us less muzzle blast?
I hope that somebody knows more about this subject and could tell us from personal experience.
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