Duplex loading in a bp cartridge rifle and in a m/l are two very different things. The brass case seals the chamber and permits higher pressures. Personally, I think if you want to get better performance in a cartridge rifle than you can get with bp, you can use (surprise) SMOKELESS. If you aren't happy with the power level of your .44mag with max loads, what do you do? Do you use overpressure loads, or do you get yourself a .454Casull or other larger case? We aren't talking rocket science here. Duplex loads in m/l are an accident waiting to happen. They are not designed to contain the pressure levels or the pressure spikes that can happen when using unsuitable propellants. You are setting off a powder charge in a HOLLOW TUBE with YOUR FACE at one end. If you want to make it into the Darwin Awards, there are many more creative ways of going about it that don't risk the lives of bystanders. If it's "not clean enough" or "not powerful enough" with bp or subs without adding a smokeless powder, the shooter has an attitude that is frankly dangerous around m/l's and should stick to cartridges (at the other end of the firing line from where my kids and I are shooting, thankyouverymuch.) There is all kinds of useless and dangerous information floating around that has been published by fools (often well intentioned, but still fools). Anyone who regularly dabbles in unsafe practices is sooner or later going to run into either the law of avarages or Murphy's Law and end up a statistic. I have no problem with such people removing themselves from the gene pool, but too often they take others with them, and I do have a problem with that.