Contemporary info on high compression black powder loads

[Roverguy]

At the apex of the black powder era for small arms, the first half of the 1880s, military arsenals across Europe are said to have been experimenting with very high compression black powder loads. We know that the 1889 debut of the 303 British consisted of a pelletized high compression 70 grs black powder load with a hole through the center to aid in uniform ignition, under a glazed card wad. The Swiss and Italian Vetterlis were subject to experiments with very high compression loads. I have seen suggestions of 60 grs for the Swiss. And there are references to experiments with high compression black powder loads by the French, Germans, Austrians, Danes and Swedes.

But other than references to such loads or loading experiments, I can’t find much data at all. One must assume that the goal was higher velocity, thereby requiring more powder. But was that it? Or did the experimenters in the Golden Age of BPCs imagine other or additional benefits from high compression? What were the results of these efforts ?

I have pretty good search skills but have been unable to find much in the way of information on the subject, let alone contemporary first hand info: publications, correspondence etc.

So, if anyone can point me to such info, I would appreciate it.

 

[Ugly Sauce]

I can't point you anywhere, (!!!!) but from my own experimentation, I've found that the more the powder is compressed, the cleaner it burns. I compress my charges a lot, I shoot the Speer 400 grain JSP over 80 grains of Swiss 3fg, and it is noticeably cleaner burning than say a load of 70 grains or less. Also extremely accurate.

For a 416 grain lead bullet load, compression to get 70 grains into the case is still quite a bit, and again, very clean burning and seems very powerful. And Accurate.

I've never chronographed loads of varying compression, but I'm sure it produces more pressure and velocity. And again, less fouling.

It would not be a hard experiment for one to conduct on their own, with a chronograph.

The picture is of my Marlin's 100 yard, 1" group, open sights, with a highly compressed load of 80 grains of 3fg Swiss, and a 400 grain bullet. Or group #3. The two other groups I was adjusting the sights.