Shamrock mark on French cannon, meaning?

I tried googling this, unsuccessfully.
“La marque Shamrock sur un canon signifie…”

‘The small stamped shamrock appears on the muzzle face and near trunnions of a French model 1828 mountain howitzer made in 1844, in France. What does the shamrock stamp signify. ?

https://flic.kr/p/2pmRYnq

 

Might try trèfle (clover).

 

Trefoil, clover, club. I wouldn't be hunting shamrocks.

 

I'd think it was a trefoil, symbolizing the trinity and a heraldic symbol.

https://en.wikipedia.org/wiki/Trefoil

According to this, it can be found on arms.

https://www.hallofnames.org.uk/heraldry-symbols-and-what-they-mean/

Debora

 

Thanks. The fact that it was applied easily and quickly via hammer and steel stamp I’m guessing signifies an inspector having approved the work in that area, say the one on the muzzle means he’s checked the diameter, straightness, etc. of the bore. Just today’s guess. Proof marks on small arms are also applied with metal stamps. Maybe shamrock was Pierre the inspector, and pine tree stamp was Louis, who knows.

 

I too think it is probably an inspectors stamp. Perhaps the barrel was re proofed at some point, hence the second stamp. I think I have a French socket bayonet with clover stamp on it, dating to between 1803-1822. Great ones for inspectors stamps the French!
Another possibility, though I do not know if this was done this late, was to mark the cannon and cannon balls with a mark, so that you knew you had the right calibre shot if they happened to be mixed up, as was usually the case in earlier times. Sometimes a simple wooden ring was used to check the size of the shot, but in earlier times they were certainly marked.