There's a few guns on coins. These are the few that I own (that I can remember) And then you have coins that were struck on 'gun metal' Russia has a couple of AK's featured on their coins. http://www.cbr.ru/eng/bank-notes_coins/base_of_memorable_coins/ShowCoins.aspx?cat_num=5117-0037 http://worldcoingallery.com/countries/Kaliningrad_all.html
Just read this bit in my Lincoln Cents book. They used spent munitions shells from training exercises and mixed in pure copper to get the alloy correctish. Apparently there was quite the backlash to the steelies.
2014 Royal Mint - First World War Outbreak 6 Coin Set A couple of pieces in this set have big weapons on the reverses:
I just bought a coin with a gun on it las week. Mainly because I went to Fort Vancouver high school though (go trappers). I like guns on coins but don't particularly seach them out.