Posted by Tom Archer on August 11, 2017, 4:20 pm, in reply to "Re: Long Chamber"
Who knows? Maybe someone was already "wildcatting" and experimenting with a longer .410 shell? My observations seem to be that the experimental hand-loaders are always ahead of the "new" factory loadings/chambering anyway, although few ever become popular enough to be factory produced; but yours is a certainly great observation on those dates.