Piling swivel for a 1915 SMLE No1 Mk3

[5thBatt]

Never heard of later piling swivels being too thick to fit but the later No4 swivel screws have a different thread to the SMLEs so don't really fit (but can be forced)

The Piling swivel on the right is the type you want but be careful if you want originality, there are a lot of made up piling swivels out there that are cut sling swivels.
The Piling swivel on the left is the later (1920s on) type & is narrower, but fits all earlier rifles.