Just a quick note. I bought one of the .45-70 Spartans a week ago. No, they are not regulated. Mine put one shot on target (25"x35") and the other may be still travelling for all I know. This was for four shots out of each barrel. Yes, there is a jackscrew adjustment under the barrels. You take a pin punch to turn this to adjust the barrels. I found out about this today by calling Remington. There was nothing in the box for paperwork, except a copy of four pages that I think was done by the manufacturer. Very sparse on info.
Tomorrow, I'm going to the range and, starting at 15 yds, fire two shots, adjust the sucker if both are on paper, move to 25yds, do it again, then move to 50 yds. Right now, the left barrel is dead on at 50 yds (I did get the sights adjusted for that barrel).
There's more info on AR, but, if you want, let me know and I'll post more here.