I owned a Wilkinson DR in 577/450 for a few years,
not as nice as this one though. The rifle will probably
regulate with a 480 gr. lead bullet at about 1300 FPS.
That's where mine worked the best and it if fairly close
to the original British load. Cases can be found and they
tend to last forever.
I do like the shot barrels, that is a nice feature.
Raff