Several reasons for possible blow-ups in days gone by have been given. One is that many shooters in black powder days had simple loading tools. Some early smokeless powders, known as bulk powders, were designed to utilize the dippers used for black in loading. Some early shooters no doubt decided to give some of the newer powders a try & if they weren't really familar with the concept of "Dense" powders simply dipped the desired Dram charge with their old dipper. A 3-dram dipper full of Infallible for instance, an early dense smokeless, would have given 50+ grains, while a 3 dram equivelent of this powder was about 24 grains, thus a double charge. As damascus was the predominant bbl mat'l at this time it often took the blame.
Another stated factor was that primers continued to be used which had been suitable for the easier to ignite black, but were really unsuited for smokeless. The result could be a partial ignition which pushed the charge a ways down the barrel & then finally the main charge ignited. This was very close kin to dropping a powder charge down the bbl of a muzzle loader & then pushing the shot charge or ball as the case may be only part way down. No more efficient method of bursting a bbl has ever been devised, the projectile itself becoming an obstruction to the powder gases. This is believed by some & I tend to agree, that this is where the tale arose that smokeless gives it max pressure at a point several inches down the barrel, because this was where these bbls burst. If however these loads had been fired in a steel bbl, Designed for smokeless, the results would have been the same, the problem was with the shell, not the bbl. Fortunatrly it didn't occur a lot & when it did the odds were just stacked that it would happen in a damascus due to their wide use. Reliable pressure tests have shown that with given loads of about the same intensity, generally speaking smokeless will generate higher pressures in the chamber, the curves will cross at about the end of the chamber & the black will carry sligjtly higher pressure for the rest of the bbl. (This is also something to consider if thinking of loading very low pressure loads with a "Slow" powder. If you do this by all means forgo a few lps of pressure & use a "Hot" primer")
Thus if a bbl which had proven suitable for use with black powder burst from use of a similar powered load of smokelss, & it burst any place other than in the chamber it was almost 100% to have been from some cause other than the fact it was Damascus.
