Filler Question.

[enfield2band]

Agree with this mostly. Air in a BP load plays no part in the chemical reaction - BP has all the oxygen it needs already chemically bound in the Potassium Nitrate (which is released when heated and there is exactly enough oxygen to combine with the Carbon and Sulphur completely). The presence of an air gap changes the propagation of the deflagration reaction within the powder in unpredictable ways because the BP grains are not initially constrained to remain in one place. Sometimes you get away with it (I have fired a BP revolver where I had omitted the filler so the BP was loose - competition event and had no time to sort it - no harm done this time) and sometimes you don't. It does seem to be more of an issue with pistols than revolvers but this is not science.

Disagree on BP detonation. Detonation is defined as a deflagration (burning) reaction which proceeds through the deflagrating material supersonically. There is no known way to detonate smokeless. There is some suspicion that it is just about possible to detonate BP, but if it occurs at all it requires extreme conditions of a kind not encountered in firearms and even then the result is deflagration which is only marginally supersonic. Note that here I an referring to the speed of propagation of the reaction in relation to the speed of sound in the medium (in this case BP), and this is neither related to the speed of sound in air or the speed of the resulting projectile or combustion gasses.

BP requires some form of containment to produce a bang when ignited - free burning rate is not fast enough to go bang. A large amount of BP in a loose pile can self confine but it takes about a pound of the stuff to produce a bang rather than a "wuff". Small confinement (such as loose in an open ended cylinder) can produce a bang with much less material.

For these reasons BP is classed as a low explosive.

High explosives detonate well supersonically and produce characteristic shattering in metals rather than bending/stretching/tearing such as caused simply by overpressure.

It is my experience that:

a) reduced loads in revolvers can increase accuracy = this is analogous to the holy grail sweet spot Mv sought by many target shooters (air, rifle, and pistol/revolver).

b) seating the ball close to the chamber mouth is most likely to give the best results.

c) I do believe that there is also a sweet spot (or possible more than one) when seating the ball below the chamber mouth, at least in my ROA, but with no filler there are two variables (adjusting a BP only load varies seating depth and the resulting Mv) so it is difficult to experiment with any good control

I don't disagree with what you are saying. I think we are looking at this differently.

I have read somewhere that the detonation velocity of blackpowder is about 950fps. Thus explosives are,as far as I am aware, determined by their detonation velocity. SEMTEX has a detontaion velocity of 5 mile per second, which is why I used the term detonation. Blackpowder changes from a solid to a gas when ignited even when unconfined. As you know smokeless does not, it burns very rapidly.

[Turnup]

I don't disagree with what you are saying. I think we are looking at this differently.

I have read somewhere that the detonation velocity of blackpowder is about 950fps. Thus explosives are,as far as I am aware, determined by their detonation velocity. SEMTEX has a detontaion velocity of 5 mile per second, which is why I used the term detonation. Blackpowder changes from a solid to a gas when ignited even when unconfined. As you know smokeless does not, it burns very rapidly.

The deflagration velocity of BP is about what you have stated. This is subsonic even in air and far less than the speed of sound in solids - while it is believed possible to detonate BP it is extremely difficult to do so and certainly not in the conditions encountered in a firearm. Even initiation of BP using a detonating booster (i.e one which produces a supersonic shockwave) is unlikely to detonate the BP itself and attempts to do so have been inconclusive. BP DOES NOT HAVE A RECOGNISED DETONATION VELOCITY (for that matter neither does smokeless).

Smokeless also changes from a solid into gasses when ignited, even unconfined. What did you think it does? Smokeless at or about atmospheric pressures burns (deflagrates) quite slowly, whereas BP burns much faster at atmospheric pressures, but the burn rate increases much more slowly as pressure increases (in fact practically linearly) whereas the deflagration rate for smokeless increases exponentially with increasing pressure.