Mis-identified

Picked these 2 up off flea bay it was rather interesting as the seller identified them as French cases.
I did a quick web search and found they are Pack 75mm cases I was a bit hesitant, he had identified other stuff as rare 1937 cases but were infact cut down cases.
As in his pics of the 2 1937 cases they were different lengths which indicated that infact they were not complete I found a pic of the cases in question and they were about a 1/3rd of their actual size
The subtle clue that these were uncut was you could make out the shoulder in the pics which lead me to believe they were as made a fact I confirmed by measuring them 272mm OAL.

They both have very good head stamps and I am well pleased to put them into my collection though I am getting no hits with B.CO or B.B.CO head stamps can a forumer assist please. (303 round for scale)
TIA
M116 howitzer - Wikipedia