Might Help While researching this I came across this bit of info on the GP. GP is is for Gaffer or General purpose shotgun.

Renko bar indicator. If I remember right, top rib marked 'W W Greener and Son works Birmingham'. Barrel marked. Serial Number 185**. That number would put it at 1877 when 1,500 guns were made by Greener that year.

According to Greeners book the exact number of GP shotguns made is impossible to be determined as the serial numbers of these shotguns were not recorded until 1968. If your gun is a Police gun then the serial number look up I did for you is correct. If your gun is a GP then it's not possible to determine the date made by serial number. Two models of GP are referenced. Standard model has no checkering and a barrel band.

The second model had a better finish, checkering and looked more like a sporting weapon, The Greener Story by Graham Greener has a lot more on this gun and other Greener arms. The book is a bit spendy but I have found it quite useful in my Martini hobby. There are contradictions in the book. The text makes no mention of a MK designation in GP's. It refers to the checkered version as Model number 2. You should be able to look at the side of the action and see what it says to determine if you have GP or a police gun. Dec 09, 2017 .

According to i-Boats, 'Nothing in the Mercury Mariner Outboard engine model numbers or serial numbers provides year information directly. The first serial number sold in a year becomes the beginning serial number. Serial numbers between that year's beginning serial number and the next fall into the same year. Search for your engine horsepower on the to find the beginning serial number for the range that includes your engine.'

Your other option is to take the serial number to an authorized Merc marine eager and they can look it up for you. Sep 27, 2014 .

W W Greener was a member of the second-generation family which had been involved with gunmaking from 1829 to the present day. Today the company still makes the finest sporting shotguns and rifles in its Midlands workshops. William Greener was the first to make guns.

After serving his apprenticeship with John Gardner in Newcastle upon Tyne he worked for Joe Manton, probably the best English gunmaker in the early 1800s. Returning to Newcastle in 1829, he set up on his own to make percussion muzzle loading sporting and military shotguns and rifles, as well as harpoon guns for the Dundee Whalers. However, there it was difficult to obtain the best materials, so he moved to Birmingham in 1844 where Greener gunmaking has remained ever since. William was an inventor and during his lifetime he invented; the expansive bullet (1835), an electric light (1846 - long before the modern ‘Ediswan’ lamp was patented in 1879), a device to open the four gates of the railway level crossing simultaneously, a self-righting lifeboat (1851) and modifications to the Miner’s Safety Lamp.

But first and foremost he was a gunmaker and the quality of his guns soon attracted the rich and famous, among these Prince Albert, consort to Queen Victoria. At The Great Exhibition of 1851 he won two gold medals and a diploma. He went on to win medals at the New York exhibition of 1853 and Paris Exposition of 1855. William wrote three books, The Gun in 1834, The Science of Gunnery in 1842 and Gunnery in 1858.

He also wrote a pamphlet - The Proof House - The bane of trade - which was instrumental in reforming the Gun Barrel Proof House in the act of 1855. After William’s death in 1869 his second son, William Wellington Greener, continued the family tradition of making high-quality sporting and military guns, and his inventions helped to develop the breach-loader to make it the modern sporting gun we know today. Probably W W Greener’s greatest contributions were, affecting the system of choke boring, and, inventing the famous cross-bolt.

The former allowed him to win all The Field Trials from 1875 to 1879 and this led most wing shots to use Greener guns to win prizes and competitions all over the world. The cross-bolt which he invented in 1867 to strengthen the action of breach loaders resulted in the strongest action, weight for weight, of any gun made. By the turn-of-the-century in 1900 he had the world’s largest sporting gun factory employing over four hundred and fifty skilled craftsmen. Like his father he wrote several books the most famous of which The Gun and its Development was published in 1881. This book, like The Breachloader and how to use it published in 1892, ran to nine editions. W W Greener’s two sons Harry and Charles took over the business from their father in 1910 and ten years later the firm was incorporated into a limited company. Production was switched to military requirements during two world wars and during the intervening period demand for very high quality sporting guns diminished.