Per H&H ledger page:
.500 Bore back action
Built for Sir W. Williams
extended rib, long top strap
lever over guard,rebounding locks
A&D snap forend
Pistold hand, cheekpiece
loops for sling
barrels 5 lbs.11oz.
Memo 9623, Lyman sight added 23/10/00

I have found out that Sir W. Williams
Born July 30, 1856
His carrer spanned 35 years as a doctor in the English military. Appointed Principal Medical Officer to the New South Wales army. Arrived in South Africa in 1899 and awarded Queens medal for medical service. Appointed Surgeon General for the Australian Medical Corps and moved to Melbourne in 1901.
Died May 10, 1910

I purchased this rifle from an Australian dealer.
John