Large bore modern quality rifles (DG rifles), either single or double barreled, typically have very good accuracy. It is the rare .40+ barrel that is not 1 MOA capable with the right shooter (note that I said shooter, not load
).
Additionally, double rifle barrels (in rifles well made) are well supported and have very consistent harmonics. This increases the chances of tight groups.
I am not aware of a specific double barrel rifle brand having a better reputation for
individual barrel accuracy, and to be honest I do not even know if double rifle makers make their own barrel blanks. I expect not.
So, I would expect barrels from Krieghoff, Merkel, Blaser, or Heym double rifles (to take a German example) to shoot about the same individually.
For example, my Krieghoff produces consistently "~MOA" groups from each individual barrel.
Note: I say "~MOA" because 1" groups at 50 yards are not 1 MOA but 2 MOA. The group would have to be 1" at 100 yards to be 1 MOA. Since I do not have the capability to scope my double, like
Red Leg's S2, and since the .470 is not designed to do what the .500/.416 is designed to to (less stopping power but 200 yards potential), I must confess that shooting the .470 open sighted or with red dot at 100 yards for individual barrel groups is not something I ever had interest in, so I did not do it...
Krieghoff .470 NE - factory load Hornady DGS 500 gr - 50 yards - Leica 3.5 MOA red dot. Good barrels accuracy but not the load that regulates best.
Krieghoff .470 NE - factory load Norma PH Woodleigh FMJ 500 gr - 50 yards - Leica 3.5 MOA red dot. Good barrels accuracy and a load that regulates well.
Krieghoff .470 NE - factory load Barnes Banded Solid 500 gr - 50 yards - Leica 3.5 MOA red dot. Good barrels accuracy but not the load that regulates best.
For those who wonder, the unusual shape of the above target is designed to emulate the size of an elephant brain in a frontal brain shot... Note that even loads that regulate around 4" at 50 yards would still be usable, although I obviously selected the Norma PH Woodleigh FMJ that regulates at 2"
Also, in my rifle at least, it seems that slugs with the classic long parallel sides, no pressure relief groove, and blunt nose, shoot a little tighter than the modern expanding monometal slugs. I do not know if this is a generality or not.
Krieghoff .470 NE - factory load Barnes TSX 500 gr - 50 yards - Leica 3.5 MOA red dot. Not the best barrels accuracy but a load that regulates well.
So, in conclusion, individual barrels from a quality double should have no issue grouping 1" at 50 yards with iron sights or red dot, and I am convinced that most of them also shoot around 1" at 100 yards if the rifle is scoped.
As to the two barrels shooting together, which is not the question here, just for memory a
good quality double, will shoot 3 lefts and 3 rights around 2" at 50 or 100 yards (it should neither diverge nor converge), with some loads it likes, and it will shoot most other usual loads under or around 4".
PS: by the way, I expect the title of the thread was meant to be "regulation" as opposed to "registration". No big deal, but just so that a term does not emerge and confuse further the double rifle new comers.