There's not a lot of information to go on. C.R.V. could be Cheshire Rifle Volunteers, Cornwall Rifle Volunteers, or another.
A John Downing Farrer was living in Cheshire (source 1861 census) and in 1862 would have been aged about 33. It's a tenuous link but its the best I have come up with!
Local newspapers are a good source for information on Rifle Volunteers. Cheshire may be a good place to start, but not having a date of the event it will take a lot of searching (and C.R.V may of course not be Cheshire!).
For background of the Volunteer Movement see the appropriate pages on this web site:
www.researchpress.co.uk/volunteers/index.htm.
Rifle shooting as a sport and a patriotic pursuit was extremely popular in the nineteenth century.
David