50.6mm; 51.4gm #2 of 4 from the Flea Market. This shows some rim damage, as from being gripped in a vise with serrated jaws...but it appears to be silver, rather than plated. The art on the obverse is superb, IMO...by PM (beneath the tip of the quiver). Note that NRA has no punctuation...and I can't intuit what it stands for. Any ideas? The message on the reverse (in case it won't magnify sufficiently) states: PRESENTED BY THE KING TO ENCOURAGE YOUTH IN THE HOPE THAT FRIENDLY COMPETITION AND EFFICIENT TRAIN ING MAY HELP IT TO FORGE NEW LINKS OF EMPIRE
http://www.dnw.co.uk/medals/auctionarchive/searchcataloguearchive/itemdetail.lasso?itemid=45865 Oops....strike that. Similar medal but I believe the reverse is different (according to the description) from the OPs'.
Poking around, I found them in different metals (bronze) and I'm wondering if they didn't make them in different sizes too.
It is for the British National Rifle Association. The medal was designed by Percy Metcalfe and apparently this design was awarded between 1925 and 1930. I've only done a little research but it seems they different rounds in the competition with the top award being a gold medal and second place being silver. I find no mention of the bronze medals, but all I find online are the bronze ones and no the silver or gold. I suspect the bronze medal may have been like a participation medal for all who qualified for the competition. Some information http://collections.vam.ac.uk/item/O313333/kings-trophy-competition-medal-metcalfe-percy/ Some more http://www.nra.org.uk/common/asp/results/queens.asp?site=NRA The second link would probably be a good source of information about the medals. It's on the NRA of the United Kingdom website.