My point exactly. The bp will, in the presense of excess O2, burn VERY vigorously, but when tightly contained in the breech of a gun with very little oxygen it will burn MUCH more slowly. Smokeless, on the other hand, when uncontained burns very hot but very slowly because the energy needed to break the chemical bonds of each nitrocellulose/nitroglycerine molecule and the reduced proximity of the resulting free unbonded nitrogen and carbon atoms which restricts their ability to form the very strong nitrogen-nitrogen triple bonds and the two oxygen-carbon-oxygen double bonds (which IS a conbustion reaction, but the reagents are created when the nitrocellulose decomposes and requires no external source of oxygen). When you contain the nitrocellulose powder and light it the molecules are confined in a high pressure environment where the as yet undecomposed molecules and the atomic products of that decomposition are very close to each other, resulting in the much more rapid and energetic recombination of atomic nitrogen into ultra stable molecular N2, combined with the release of a truckload of energy compared to the weaker reactions from combustion that occurs with BP. The energy to initiate combustion in black powder is also much lower than the energy needed to break the molecular bonds that starts the decomposition of smokeless, which is why black powder burns nearly explosively when uncontained.

Mike