I am today sending six pages of serial numbers to L61R, taken from a 1983 issue of Finnmark (the SCA newsletter). There are no listings for the 220 Russian or the 220 Swift. These serial numbers end in 1979, so that I assume the Swift came later (I have an AII HB that I special ordered in 1989). However, there is a L461 .223, S/N 113140 produced 1-3-70. That is close to the S/N you report. I cannot find an L46 produced in any caliber after October, 1961. Perhaps someone can provide Swift production dates and serial numbers.
Take an empty .220 Swift (remove bullet and powder) and try it but do not force it. If it fits, you have your answer. If the chamber seems to be shorter, either try an empty .220 Russian or have someone with go and no go guages check it.
Take an empty .220 Swift (remove bullet and powder) and try it but do not force it. If it fits, you have your answer. If the chamber seems to be shorter, either try an empty .220 Russian or have someone with go and no go guages check it.