Hi,
I'd say a box of 12 bore "Rockets" goes for around £5 - £7 amongst experienced collectors. The ones pictured are post 1936 and pre 1939, the brand didn't emerge after the war. The pre '36 Rockets have different box and case print, most notably is the rather old fashioned use of SHEWS, as opposed the SHOWS[the flight of the shot].
I have examples in 12, 16, 20 and the wartime cream/red version with a broad arrow mark. Non of these (along with most Eley-Kynoch ICI) brands are regarded as scarce by collectors, value for and individual shell is around £1 or £2.
I have seen variations on the cartridge with an FN belgium head-stamp, made under license, and an all orange cased version, presumably no grey cases on hand.
In terms of collecting cartridges in general, the rule tends to be; rare Ironmenger or gun maker - good, propriatary brands,e.g. Eley, kynoch - not so good. there are of course always exceptions and I'd urge anyone to consult an experienced collector before disposaal, you may be holding something rare and [relatively] valuable.
I'm at around the 1500 pre WWII British paper rolled-top mark, and always keen to buy or swap to get new examples. you can reply to the thread or get me at tony-green@tiscali.co.uk
I'm always happy to help with questions, provide photos WHY
Cannonite
