Bonny: that Purdey is manufactured using Damasteel http://www.damasteel.com/
Production methodology
http://www.damasteel.com/production.html
http://machinedesign.com/article/damascus-steels-from-powder-metal-1118

In a 2009 press release "Purdey's Secret Weapon", Purdey announced the production of an all Damasteel shotgun.
"All parts other than springs, tumblers, seers, cams and non-visible screws and pins are fabricated from (Damasteel.) Each visible part of the gun- action, forend iron, triggerplate, bow and guard, rib, fins, etc.- were cut from re-forged billets so as to procure the best display of the pattern available in the steel."

https://sites.google.com/a/damascusknowledge.com/www/home