Well, I took the 1841 Mississippi Rifle (Euroarms) to the range last week. In short, the Big Desert did not seem to work well as a patch lube. I was getting inconsistent patch wear, even had one "smoker" out in the grass.
That said, I may not have been using enough lube. The only "thin" patch lube I use is spit. My usual is more of a cream than liquid, so user error may be the cause here.
I was applying the Big Desert Lube as I shot, perhaps the patch needs to soak in it a bit to become fully saturated. The patches looked lubed, but may not have penetrated enough.
I'm not writing off this product yet, back to the range to learn more!