After some preliminary measurements, 11.6X65R it would appear it may approach the 450 2 1/2"



10,8mm by E. Joris & Co. @ the Liege proof facility. Then in 1900 it passed the Wien proof facility @ 11,5mm and again in
1909 @ 11,6mm. More to come.



Cheers,

Raimey
rse