Well, you didn't specify the denomination, but let me tell you what the legends mean.
1896 is obviously the date on the coin, Victoria is who is depicted on the front of the coin. Dei Gratia means by the grace of god. Britt Regina means queen of the British. Fid def means defender of the faith, and Ind Imp means Empress of India. Put these together and you get part of Queen Victoria's royal title, Victoria, by the grace of God, queen of Britain, defender of the faith and empress of India.
As for the mintmark M, this mintmark would only appear on the gold coins, the sovereign and the half sovereign for this date. The mintmark would be above the date on the reverse between the 8 and 9 on the ground with St. George slaying the dragon. This mintmark means the coin was minted in Melborne.
That motto is on ALL British coins so it doesn't help to ID a specific coin. Please post a new question with the coin's denomination and an estimate of how worn it is.
It will be either a British Sovereign or Half-Sovereign.
There were no Australian (or Western Australian) Pennies minted prior to 1911. An image of Queen Victoria and the inscription VICTORIA DEI GRA BRITT REGINA FID DEF IND IMP (Queen Victoria, by the Grace of God, Queen of the British Territories, Defender of the Faith, Empress of India) or similar, would have appeared on the obverse of any official British coin minted in 1896. What you may have is a Traders token or a medallion. The reverse may have a business name and address on it or, some sort of commemorative inscription.
You are the second person to ask about an Australian coin that, in theory, should not exist. Can you provide any more detail about your coin?
With the British military, all arms are the property of the Crown, and are marked as such. Your rifle was made during the reign of Queen Victoria, hence the VR (Victoria Regina) 1896 is likely the year of manufacture.
No Carson City Morgans were struck in 1896
Victoria Bachke was born in 1896.
Regina Yanushkevich was born on August 18, 1896, in Vizhuny, Russia [now Vyzuonos, Utenos, Lithuania].
Queen Victoria
Please look at the mintmark again. The Denver Mint did not exist in 1896. Post new question.
Queen Victoria
Such a coin does not exist. Queen Victoria was monarch in 1896. King Edward VII from 1901 to 1910.