I want to know the answer to the following question:
What gun size was relined to take 13-pounder shells?
All the background I'm provided with is that "All armies soon deployed AA guns often based on their smaller field pieces, notably the French 75 mm and Russian 76.2 mm, typically simply propped up on some sort of embankment to get the muzzle pointed skyward.". Is that enough to answer the question?
Answer: no