As per Skennerton's WWII Contract book, Britain purchased Winchester .22 rifles from the trade and from the US.
I have a few issue Winchester .22 rifles with pre-WWII proofs (ergo taken in from the trade/dealers) with a stamped five digit number added to the left side of the barrel. Winchester .22s of the period are not serial numbered in the US.
I was told that the numbers were added by Winchester prior to export to England as a serial number was required-- probably proofing records. Can anyone confirm this or did the proof house add the numbers?