Capacity wise, it will be nearly identical to the 7mm RUM just as the 7mm-338 Lapua is. Just as the 338 Edge and 338 Lapua are nearly identical in performance.
IF the Norma case is of similiar strength to the Lapua case, they will likely be able to drive same weight bullets slightly faster then the RUM based rounds of same caliber simply because of case strength but that has yet to be proven from what I have seen.
In my testing of the 7mm caliber on my improved design on the Lapua case, I can tell you that bullets lighter then 140 gr is pretty much just playing. YOu really need at least 160 gr of bullet weight to make this type of case settle down and 175 gr and heavier is even better.
Top performance will greatly depend on the receiver the rifle is based on. For example, my 7mm AM will get 3550 fps with a 175 gr SMK when using one of the stout custom receivers such as BAT or Nesika or similiar. In the lighter receivers such as the Lawton and even the Stiller to some degree, you will get pressure signs around 75 to 100 fps less in velocity.
Again, this is a 7-338 Lapua Improved design. IF your looking at a standard 7mm-338 Norma Mag, expect 100 to 125 fps less velocity then this. This is assuming that the Norma case is on par with the strength of the Lapua case which again, is yet to be proven in my opinion.
