Canons

[werecow]

Originally Posted by df1967

Just the producer sign HF I really have no idea.

I have no knowledge to speak of at all about canons but regarding the HF marking: this one looks relevant and fits with corrado26 suggestion that it may have been Scandinavian. The description:

A SMALL SWEDISH IRON CANNON, HÄLLEFORS FOUNDRY, 19TH CENTURY formed in five tapering stages divided by mouldings, plain trunnions with the letters ~HF~ in a rondel between, raised vent field and globose cascabel 28.3 cm; 11 1/8 in barrel 1.6 cm; 5/8 in bore Property from the David Jeffcoat Collection (1945-2020) Part proceeds to benefit The Wallace Collection Hällefors, west of Stockholm, was an important iron founding centre from the 17th century.

(emphasis mine)