I did say it is a Jovino gun, but neglected to state that it is apparently one of those built-up from spares. The receiver is dated 1943, while the stock parts are 1942. The serial number is 771A, which is one of the series applied by Jovino, as I understand it.
It looks good, and shoots so well, that it is an irritant to have excessive headspace. I bought the rifle as a shooter, and would much prefer to have its mechanical aspects up to spec., and avoid the need to resort to dodges to save the brass for reloading.
It appears possible to correct the problem with new parts, and I'm going to try that.

mhb - Mike