Thread: Ulrich Bretscher's SMOKELESS BLACK POWDER & HANDGONNE web page. Re-found!

Originally Posted by canross

Thanks Cordite! I see what you're saying around the comparison of his two home made powders.

I think I usually write too much without being very clear - what I was trying to say (poorly) was I was curious about whether the sulphurless BP would behave the same was as sulphur based BP when compressed as part of the manufacturing process. You can make BP without pressing into pucks before graining it into Fg, FFG, FFFG etc, but you'll get a very light fluffy powder. Pressing into pucks then corning it down to the appropriate grain size gives you a "standard" powder. I have no idea what that standard is, but it seems like there is one. Again, I haven't done it, just read about it.

I didn't see Ulrich's write-up mention compressing his powder so that the mass (1 gr) matched whatever the accepted "standard" density of BP is, which apparently affects burn rate (from what I've read: as powder density increases from pressing, burn rate decreases). In that way I suspect that home made powders by their nature are faster burning than commercial powders because they are lower density, but at the cost of being less robust and bulkier.
Since we have powder measures that have volumetric graduations, and most countries historically used volumetric measurements for their powders, there must be some sort of accepted density for powders that most current commercial companies follow where they can say that X weight of BP equals Y Volume of BP. I know historically that exact density varied between countries, but within one area of standardization (military, country, region, alliance) they tried to keep that density fairly consistent so one batch of powder wouldn't be significantly stronger or weaker at a given charge volume than another (though it did happen as angry letters from supply agents to powder mills and officials demonstrate).

If the whole "density increase=burn rate decrease" thing is correct, then I'm curious if the two powders (sulphur and sulphurless) might behave the same or differently when compressed as part of manufacturing. Might be that the sulphurless stuff burns faster than its sulphur counterpart when compressed, or maybe it burns slower, or maybe compression doesn't affect it any differently than its identically treated sulphur-using counterpart. Maybe it's even harder to ignite when compressed, maybe it's easier. I'd assume that it would continue to be 10% less powerful in compressed form than its sulphur counterpart.... but maybe it isn't? If there wasn't a significant decrease in performance it would at bare minimum mean you could use your standard volumetric powder measure to measure loads with your muzzle loader and not have to offset your charge weight because it was a sulfurless powder.

Anyways, that's me rambling. It would make a fun experiment I guess is what I'm trying to say at the end of it all.

Yes, lots of unknowns. Sadly... I don't think anyone on this forum will invest in a 30 ton pressure BP mill to find out. This is the commercial powder difference.

Anyway Bretscher found that, by weight his homemade sulfur BP was more powerful than Swiss commercially milled powder! The dense commercial kernels help get a lot more charge into a fixed cartridge space but does not seem to make the best out of the powder otherwise. This is good news for muzzle loaders who want to make their own powder as they don't have to make compromises. They can load by weight. And if you want to load subsonic loads you might even get enough into a cartridge case!

Got a tin of sulfur free BP sitting there and some of shooternz's 212 grain .303 boolits, life on the range is going to be good post-lockdown, but I must remember to bring a cleaning rod... (O: