Franc, a rifled NEF slug gun is certainly the quickest and least expensive route toward throwing big chunks of lead down range accurately. It is indeed too bad that they are so homely.
PM, I have not worked with 10 bore, but have had two of the Pedersoli Kodiak SXS percussion rifles in .72. I will agree that 150 grains of FFg under an 835-grain Fosbury slug will command one's attention. I cannot recall what this load chronographed.
Graeme Wright reports the original BP Paradox ballistics as 750-grain Fosbury at 1000, with the later smokeless "Magnum" giving 1300-1500, and the Westley-Richards Explora Magnum a 730-grain slug at 1500. Plenty of punch on both ends in 12 gauge.
The 10 bore paradox = 220gr BP and a 925gr bullet. The later Holland smokeless load gave the same ballistics using pistol cordite.
