Belgium ?

[OH Osthaus]

here is a picture Herb sent me of the mark in question-
for the second one I tried to highlight the mark -

Herb- it's a gun or barrel maker's or importer's mark - not a proof mark - I don't recognize it but maybe someone will
is there a set of marks on the underside of the barrels? or the watertable

[Herb Hewlett]

the mark on the watertable is mostly gone,it looks like it was a triangle but just
the corner of one side is visable ,other than that 16r,a serial#15852,and1941,70 Thanks,Herb