Here is info on Dickson from the IGC, probably more than you wanted to know

:
A John "Dicksoune" was apprenticed in 1623 for 7 years to Patrick Hamiltoune, gun maker; in 1625 he was mentioned in a list of masters and apprentices. Another John "Dickson" (son of William Dickson) was apprenticed as an armourer to James Miller in 1606. A Gilbert "Dikson" was an armourer c.1835-1840. It is not certain that any of these men were connected with the later Dickson family, but we think it worth mentioning them.
The John Dickson who is known in connection with this famous firm was born in 1794, the son of John Dickson a wine porter, and his wife, Elizabeth.
On 13 October 1806, at the age of 12, he was apprenticed for 7 years to James Wallace at 187 High Street, Edinburgh.
In 1811 John married Margaret Henderson, but they only had their first son, also named John, in 1820 (he was followed by a further five children).
In 1813 John finished his apprenticeship but was employed by Wallace as a journeyman until 1821. In that year he became an outworker working for Wallace and others, but in what precise capacity is unknown. In 1828 James Wallace moved to 63 Princes Street, John Dickson probably moved with him but he was recorded as a gun maker at 63 Princes Street only in 1830; it seems that his separate business shared the premises with Wallace.
In 1840 John Dickson together with his eldest son, John, leased 60 Princes Street where they traded as John Dickson & Son, and the first recorded Dickson gun (serial No. 1590) was made (guns engraved Jno Dickson & Son are common, Jno being a common abbreviation at the time). The Dickson family lived at St James Place West.
In 1849 he bought the business of A W Agnew (formerly Wallace & Agnew) and moved back to 63 Princes Street. At some time after this date, the firm installed a stuffed lion in their shop window. The lion was later to be adopted as the firm's trade mark appearing on their stationery, gun case labels etc.
In 1858 the firm made their first breechloading gun, a double barrelled pinfire shotgun (serial No, 1928).
In 1860 the family lived at 17 Blackett Place; John Dickson's wife, Elizabeth died there but later, John Dickson married Barbara Young who was 20 years his junior. She died in 1864, and he married again, this time to Georgina Milne.
From 1865 the firm made breechloaders using Richard Brazier's patent action 259/1864, they later used the Thomas Horsley, Westley Richards, Charles Lancaster and Purdey patents.
In 1873 at the age of 72 John Dickson retired and his son took over the business.
In 1875 the firm started to do business with an eccentric collector, Charles Gordon. Gordon ordered a double barrelled breech loader and went on to buy 300 guns over the next 30 years. He never fired any of the guns and only stopped buying when his family took out a Court injunction to stop him. Many of the guns he ordered were out of date at the time he ordered them, so it seems that he was fascinated by the development of guns and sought to amass a collection by one maker which would illustrate their evolution.
John Dickson, the father, died in June 1880, and Georgina died four months later. At about this time, the firm described themselves as gun makers and estate agents, but presumably they acted as agents for shooting and stalking rather than the buying and selling of land.
It was on 23 January 1880 that John Dickson II took out his first patent. This was No. 294, and it was the first patent covering the famous Dickson Round action gun.
On 23 February 1882 John Dickson II and Andrew Graham Murray (an Edinburgh lawyer) patented a three barrelled shotgun (side by side by side: patent no. 873) which referred to the previous patent No. 294 and in which the lockwork and hammers were again built as a single unit with the mainsprings at the rear. Twenty seven of these guns were made.
Around 1880 two of John Dickson's (II) sons, John and Peter, joined the firm. John, the grandson, being the elder of the two, became a partner first with Peter becoming a partner in 1885 when John Dickson II died aged 66. John Dickson III, the grandson of the founder of the firm, married Elizabeth Bogle in 1886, they had no children.
On 2 July 1887 John Dickson III registered patent No. 9399 for ejectors for the round action guns, and on 2 August 1887 he registered a further patent No. 10621 which covered improvements to it.
In 1892 Peter Dickson drowned when the ship he was travelling on to Australia sank in the Indian Ocean.
In 1916 the firm appears to have bought some of the stock and machinery when Dan'l Fraser closed, but not the name and goodwill of the company.
In 1923 John Dickson III died and the firm was sold to A M Prain (son of William Prain of Montrose who with McArthur had invented the "Gannochy" cartridge loader). The firm continued to operate under the John Dickson & Son name.
In 1928 the firm moved to 32 Hanover Street.
In 1936 the firm became a limited company, John Dickson & Son Ltd, and in 1937 they moved to 21 Frederick Street. During the 1930s the firm had shooting grounds at Costorphine Hill.
In 1938 D Hayhoe, formerly manager and then owner of Mortimer and Son (and Joseph Harkom) bought the business, thus Dicksons acquired the Mortimer and Harkom names.
In about 1940 the company bought the business of Forrest & Sons of 35 The Square, Kelso. They traded under the Forrest name until about 1988.
In 1947 the firm bought the business of James MacNaughton at 26 Hanover Street, they probably closed these premises within the year. At this time the firm had guns made for them by S Wright & Sons of Birmingham (Capital and Caledonian models).
In 1964 the firm bought the business of Alexander Martin (incorporating Alexander Henry). Alex Martin occupied Alexander Henry's old shop at 22 Frederick Street, Edinburgh, they closed this shop in that year. John Dickson & Son Ltd (incorporating Alex Martin) traded at Alexander Martin's old shop at 25 Bridge Street, Aberdeen until 1971 when it moved to 35 Belmont Street, Aberdeen; it closed in 1985. The Exchange Square, Glasgow, shop remained open until 1988. It is believed that Alastair Sinclair (formerly of Alex Martin) became managing director of Dickson & Sons, a post he held until 1985.
In 1967 the firm took over William Garden of 216 Union Street, Aberdeen (incorporating Charles Playfair).
In the 1960s one of the shareholders in the firm was a Mr Laing (father of Alasdair Laing). He and Barry Wilcox bought the rights to the name of James McNaughton. In 1998 Alastair Laing and Barry Wilcox bought the rights to the name and goodwill of Dan'l Fraser, and in 1999 they bought the shares in Dicksons which they did not already own, and re-named the firm Dickson & McNaughton.
At an unknown date Bob Palmer and Gil Hodge, both from Texas, invested in the business. It has been reported that at some time Arthur Winguard was a shareholder.
Internet Gun Club has some details of serial numbers and dates; John Dickson & Son hold more comprehensive records of some of the guns made by John Dickson & Sons, James MacNaughton, Alex Martin, Thomas Mortimer and the new firm of Dan'l Fraser.
The firm sold cartridges under the names "Capital", "Pegamoid (post 1927), "Jubilee", "Ejector", "Lion Twenty" (post 1920), "Lion Special" (post 1927), "Lion Sixteen" (post 1927), "Special Blue Shell" and "Dickson's Favourite".
Here is their website and contact info:
http://www.dicksonandmacnaughton.com/Dickson & MacNaughton
21 Frederick Street
Edinburgh
EH2 2NE
Tel. 0131 225 4218
Fax. 0131 225 3658
E-mail. info@dicksonandmacnaughton.com
Pete