Never really got to play with one... but I think on the left side would be more natural. At least as far as opening the action
Speaking of opening the action, kind of surprise that no-one else other than Dickson made a side opening O/U? Seems like it make for a svelte shotgun... Yet another late 1800s creation!
Pictures from
Bonhams website
12-bore side-opening over-and-under round-action ejector gun by J. Dickson & Son, no. 4178, The first of only four ever made
Incorporating John Dickson & Son's patent number 215, sidelever-opening, the treble-grip action-body with the makers name in a scrolling banner surrounded by best foliate-scroll engraving, the highly-figured stock with pistol grip and horn pistol grip-cap, the barrels engraved
John Dickson & Son, 63 Princes Street, Edinburgh with matt top-rib and horn-tipped wooden side-fillets, the right with lever-latch release
Weight 7lb. 4oz., 14¾in. stock, 30in. barrels, approx. cyl. & ⅜ choke, 2¾in. chambers, recent London nitro reproof
Footnotes
The makers have kindly confirmed that the gun was completed in 1888 for Schomberg Kerr, 9th Marquess of Lothian