Charles Heath wrote
Can anyone recommend a good source on hand grenade launchers or light mortars
(e.g. coehorn mortars) from the late seventeenth through first quarter of the
eighteenth century?
 
 
A 1683 inventory of the tower of London lists grenado shells of 18 1/2 ins
diam down to 4 1/4. A 1701 inventory lists them from 18 1/2 to 4 ins  and in
1713 from 18 1/4 to 7 3/4 ins as well as shells for coehorn mortars.
English Cohorn mortars (the smallest standard mortar) had a calibre of  about
4 1/2 ins and appear in tower inventories from 1713.
Your grenades thus seem to be the right size for hand grenades and a bit
small for Cohorn mortars though presumably could be fired from them-though
this seems unlikely.
However, Hand mortars with snaphaunce locks appear from 1688 in Tower
inventories and according to Pollard's History of Fireams ed. C.Blair, London
1983, p. 153 were use by 1723 in England and the Continent.
All the other info  info comes from H. L. Blackmore, The Armouries of the
Tower of London, vol 1. ordnance, London 1976
Paul Courtney, Leicester, [log in to unmask]