If a gun shot exactly the same from day to day under any and all variables, there would be no need for windage adjustments on scopes. No need for sighters in benchrest competition. There is no such thing as set it and forget it. No gun shoots exactly the same from day to day. It could be dead on all day tomorrow and with very little change in the variables, it could be off the very next day. Comparing one gun to the other gun is useless. That induces different affects. Different stock configuration, different pressure on the stock due to your hold, different recoil from one gun to another. One recoils straight back, the other recoils slightly differently because the stocks are not the same geometry. The list goes on and on.
Bullpups: They are top heavy. They tilt from side to side very easily. It's not unusual to see lateral stringing. They are ok off a bench or sandbags but not nearly as good as a gun designed for bechrest. The Royal is much better suited for this , which is probably what you're seeing.
The real test for an accurate gun is not micro adjustments to hit dead center on target. But rather if the projectiles are going hole for hole. Or close to it, At the same point of aim.
Something to think about.
T.A.