Jerry, all reasons are legitimate reasons,as long as the scope is properly installed. Installing a scope in QD rings & bases is not as simple as it is on a single shot, or bolt rifle. There are dynamics that must be addressed when mounting a scope on a side by side double rifle, that don't exist with the single shot,single barreled break top single shot, or bolt rifle. the single barrel rifle only recoils up, and back! Not so with a S/S double rifle!

Many order their double rifle regulated with the scope of their choice, without understanding the dynamics of the S/S double rifle's regulation! First the S/S double rifle absolutely must be regulated with the iron sights! Then the scope must be chosen with extreme care! By this I mean the weight of the scope and all mounting hardware must be as light as in possible, while still being strong. The QD bases, and rings must return to zero absolutely! The scope must be mounted as low as is possible as well so that the mounting of the rifle comes as close as is possible to the same mounting for the iron sights. All this may sound silly to most people, and even most gunsmiths. This is because they do not understand the reasons these things must happen.

The side by side double rifle without the scope attached recoils up,back, and to the right when the right barrel is fired. The opposite happens when the left barrel is fired. The single barrel rifle doesn't do this, so the scope must be very carefully selected, and mounted by a smith who understands this! The weight of the scope & mounting hardware drriectly effects the UP, and back motion of the rifle, as it does on a single barrel rifle. But that weight, and how "HIGH" you mount the scope negatively effects the rifle's ability to "Flip" to the right for the right barrel, and to the left for the left barrel, thus effecting the position of the muzzles of each of those muzzles when the bullet exits the muzzle of that barrel. The heavier, and the higher you mount the scope, the more it will effect the regulation dynamics of the rifle! The little thing called BARREL TIME's bullet exit, is either lengthened, or shortened by the reduction or addtion of weight on the barrel set!

So to add a scope to a double rifle, everything included must be as light as is posible, and mounted as low as is possible, to work properly. The very best for the person needs the scope because of eye sight, is a 1X scope with a German post reticle, with an illuminated tip! This way he can shoot with both eyes open, for fast action, and close on eye for pin point accuracy!

Still, properly done, there is no more reason not to mount a scope on a S/S double rifle than there is aa single barrel rifle, but it absolutely must be done by a man who knows what he is doing when it comes to the S/S double rifle, and the more recoil it has, the more carefully it has to be done! Let me say here, IMO, if one wants to mount a scope on a between the wars, Britt double rifle, then it needs to be done by the same company that made the rifle, and documented as Factory done, if the collector value is to remain intact! COOOSTLY