Had a 20ga SXS with RIFLED barrels built last year. It's on what was a FN 16ga sidelock action. Took it to the range this weekend to see how it shoots with 3 different slug loads.
Shot all 3 loads at about 25 yards after boresighting it so it'd be on the paper. Shot them off a bench but with the gun supported by my hand and only my elbow resting on the bench.
That's the way a Double Rifle is shot so I did it that way. I uderstand that for the barrels to regulate properly it has to be shot using hands only so that it recoils and rolls.
The first picture is Buckhammer Reduced Recoil.
I was surprised as how close the barrels put them to one another. They did not kick all that bad even though the shotgun weighs only 7 pounds.
The second is Brenneke. You can see the shape of the holes is much different. They recoiled more, maybe 20 %. Did not shoot as tight a group but still plenty good for hunting.
The last is of 2 Hornady Sabots. My wife has used them to good effect on hogs in the past. They are about equil to a 45-70 in power. Have a 260 grain bullet. ( .44 cal. I think ), at a advertised 1800-1900 FPS. They had a good kick to them.
After adjusting the sights we set up clay targets on the backstop at 50 yards and did some off-hand shooting. It was not a problem at all to hit them using either the Buckhammer or the Brenneke. Did not use the Hornady for this.
Next trip to the range will involve longer ranges and more experementaion with the Hornady.
What may be dificult will be how the barrel regulation holds up at longer ranges.