They wer emade in E. Europe and imported by Remington. My bud bought one in 30-06. Workmanship wasn't good and the rifle didn't shoot true at anything like 06 range.
It's REALLY expensive to build a good double rifle, more so than a double shotgun, which is also really expensive, the good ones.regulating the barrels is difficult to get them to hit in the same place.
I've converted a few sxs shotguns to double rifles with barrels threaded on both ends to accept changable "bushings" that's in turn threaded into the shotgun barrels at both ends. By making slightly offset or off center barrel threads I can "regulate" the barrels to both hit same point of impact at a certain distance (usually 50 or 100 yards). Your local gunsmith should be able to easily do the same. In that way you can have a double rifle in whatever medium pressure or lower caliber/cartridge you choose. I do install front & rear sights after doing this. NO I'm NOT trying to get business-just giving you the idea.
i purchased the 45/70 double from Remington/baikal.i was amazed at how well it indeed did shoot,3 inch groups at 70 yds without any mods to it ,i have since added some extras on it and have put a front stock from a coach gun on it for a meatier look,it has become my favorite rifle,and i have many.it also draws alot of attention at the range.if you can still find one it is worth the $,i have read many stories about them that were not that good,they must have changed something in the last couple of years?
A friend of mine had a gunsmith convert a Red Label O/U to a 45-70 O/U with 22" brls regulated at 75yds. It turned out real nice and shoots excellent groups. It was "pressure tested" with 405 gr slugs over max 300gr trapdoor charges with no pressure signs. We don't know if it will handle the same loads as my Guide Gun but "trapdoor+P" loads with 405gr HC shoot one hole at 50yds. Killed some hogs extremely dead last year.