Jim Watson
New member
Jet effect lot more obvious in a rifle that has half or more powder mass as bullet than a pistol that might get to 10% for a Magnum, much less for a .45 ACP.
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DASA owners
- Thread starter Black Wolf
- Start date
Pressure is a misnomer since I can apply phenomenal pressure very slowly (hydraulic) and the gun would experience no "recoil" as the bullet crept down the barrel.
OK, and just how would you apply that hydraulic pressure and still mimic the powder gas pressure??
To be a fair comparison, in all aspect but speed of propagation, the hydraulic pressure would have to originate from the same place in the gun, push equally in all directions, equal (approximately) the psi level of the gas pressure, and both the gun and the bullet must be free to move.
I don't see a way that could be done in reality. In theory yes, but how could you possibly appy the same amount of pressure that the powder gas does slowly??
Particularly if the gun is a revolver?? Where you have a pressure vessel only as long as the cylinder? Powder gas pressure builds up high, fast, faster than it can be significantly vented until the bullet exits the bore.
Applying hydraulic pressure slowly would push the bullet slowly until there was a vent (cylinder gap possibly) that would vent the pressure as fast or faster than you were increasing it.
Also, using Newton's laws the pressure is pushing back as much as forward (pushing the bullet) and isn't that reward force what we term recoil?? Adding the pressure slowly will change the amount of time to get to full pressure, so that would have an effect on the velocity of the gun, would be lower, low enough to need special instruments to measure it, but I think it would be there.
Thought experiment.OK, and just how would you apply that hydraulic pressure and still mimic the powder gas pressure??
To be a fair comparison, in all aspect but speed of propagation, the hydraulic pressure would have to originate from the same place in the gun, push equally in all directions, equal (approximately) the psi level of the gas pressure, and both the gun and the bullet must be free to move.
I don't see a way that could be done in reality. In theory yes, but how could you possibly appy the same amount of pressure that the powder gas does slowly??
Particularly if the gun is a revolver?? Where you have a pressure vessel only as long as the cylinder? Powder gas pressure builds up high, fast, faster than it can be significantly vented until the bullet exits the bore.
Applying hydraulic pressure slowly would push the bullet slowly until there was a vent (cylinder gap possibly) that would vent the pressure as fast or faster than you were increasing it.
Also, using Newton's laws the pressure is pushing back as much as forward (pushing the bullet) and isn't that reward force what we term recoil?? Adding the pressure slowly will change the amount of time to get to full pressure, so that would have an effect on the velocity of the gun, would be lower, low enough to need special instruments to measure it, but I think it would be there.
Imagine a barrel who's inside diameter started at .452" at the chamber and gradually decreased until .224" at the muzzle.
Further, imagine a propellant that changed from solid to gas quite slowly, (seconds), to a maximum 300k psi.
We load our cartridge with a .452" bullet propelled by our magic powder. Insert it, close the breech, and fire the cartridge.
At some pressure the bullet moves forward, and the total volume of space behind the bullet increases - the pressure drops. But the diameter of the bore decreases, so the pressure rises to continue swaging the bullet. But the propellant phase changes very slowly, so the bullet moves very slowly, and the pressure continually increases.
So we have a very high pressure, a very slow moving bullet. During the time the bullet is in the barrel, there will be very little "equal and opposite reaction". When the bullet finally clears the barrel, the resistance of swaging will drop to zero, and because the pressure is still quite high, the mass of the gas will eject at a very high velocity, and there will be noticeable "equal and opposite reaction".
But during the trip down the barrel, because the velocity of the bullet was so low, there will be very little "equal and opposite" even though the pressure was very high.
I've used some of that BB .357 180 grain. Don't think I'd care to shoot it in a revolver smaller or lighter than a S&W K-Frame. Not because of any strength issues with a lighter gun, but because of my old wrists. It did actually produce 1400+ FPS in my 4" and 5" revolvers, and 1500+ FPS in a 5.5" gun. That being said, extraction was easy, no pierced, leaking or unusually flat primers. Just no issues to report with the BB .357 180 in my S&Ws, or in a Ruger Blackhawk Bisley..