It was made in 1946 but needed re-sleeving in 1962.

Unless the barrels suffered some accidental damage (being driven over seems surprisingly common) this may show how corrosive shotgun cartridges were in the UK in the years following World War 2.

.410 cartridges do not seem to have benefited from non-corrosive primers until the early 1960’s, and cleaning with Aquaoil (a water based solution to dissolve the corrosive salts) was still,being recommended.