Thanks for posting the link Stan. Hollowell does a great job with images and I took the liberty of enhancing 3.
It is a 1881 Patent Pieper "Original Diana" barrel
This tiny ad from
Forest & Stream in 1882 indicates that the tubes were inserted into the monobloc
from the rear. The "Modified Diana" tubes were screwed in
from the front and did not have the step.
I have probably not been paying attention, but have not seen the muzzle steel segment before. The damascus pattern is a very nice 4 Iron "Turkish"
Interesting stuff on the flats. The gun was proved with "Schultze" which, like "E.C." was a 42 gr = 3 Dr. Eq. powder. The Belgian proof house started marking the powder (also using Mullerite) after 1891. The load was often marked 1897-1903 and most of the guns so marked used "E.C. No. 3", so I suspect the gun dates to pre-1897.
No idea who 'HB' was unless the barrel joiner/finisher.
The crowned "JL' is interesting. Pieper of course had his own tube production, but likely sourced from other Liege makers. 'JL' was probably Jean Lejeune of Nessonvaux.