There was a rumour circulating a few years ago that when Tom Skeuse was having Winchester's Olin-Kodensha plant develop the Repro that Skeuse obtained a 20-gauge DHE Remington-built Parker from Del Grego's shop that was in for a doubling problem and it was this very gun that was cloned for the Repro and it was such a perfect copy that the cloned guns also doubled!...maybe there was something to this rumour?

As an aside, one of my Repro's (a 28) is a single trigger gun, it has never doubled---yet!