Been trying all kinds of google searches for it under a number of different syntaxes. But the results are full of magnetic force line / explosiontopics. If you can direct me to a particular reference, i think I would find it very interesting.

It occurs to me that the cylinder shapes the explosion in line with the barrel. Still the gap between cylinder and barrel must have some effect, acting like a muzzle brake. A muzzle brakeworks to reduce recoil because it is capable of lessoning the motion of gas in line with barrel, thereby reducing momentum in that direction. The ideal braking would occur where the maximum velocity (congruent with barrel) the gas ever achieved was only that of the projectile. Without a muzzle brake gases remained contained and moving in the direction of the muzzle until the projectile exits allowing rapid expansion and acceleration of the gases to velocities well beyond that ofthe exiting bullet.

Pressure is the reason why a muzzle brake works. If all of motion of the gas particles were in the direction of the muzzle, then none could exit the muzzle brake. But because the gases are contained, and pressures elevated,the random character of their motion (mean speed) far exceeds their mean motion(avg velocity)which is determined by the motion of the projectile itself. I think you would agree, that for the entire breech volume, at any given point in time, the average velocityfor all the gas particles must be less than the velocity of the projectile. Near the ignition point the average approaching zero while nearer the projectile approaching the velocity of the projectile.

Regarding the revolver,certainly some portion of thegases will be accelerated past the cylinder into the barrel making impact with the projectile causing further acceleration of the projectile.The question I have is, is it significant? I can thinkthe most useful way to measure it would be to measure the efficiency of the revolver barrel.

To calculate that one needs to know what the energy is at exit from the cylinder.Subtract that energy from the energy at the muzzle of the revolver and we get the actual change in energy resulting from transit in barrel. Then if one measures the muzzle energy from a barrel which lengthis equal to cylinder length + revolver barrel length, he can subtract the cylinder energy and compare the final energy changes. By dividing this figure into the revolver barrel's change, the ratiowould reflect the efficiency as a consequence of gas spillage at the cylinder/barrel junction. So if the change in muzzle energy of the revolver were identical to that of the solid barrel, the efficiency would be 100%.

The efficiency of the revolver barrel does indeed interest me. I hoped some one might know something whichwould help to determine that.