With over a dozen years of 6.5x284 Norma shooting with a few different rifles, I dug into my records. As mentioned in my previous post, while I did some early loading with Norma(Nosler) brass, the majority of my shooting has been done with Lapua brass, but results were quite similar using the same load parameters between the two cases. The neck-wall thickness between the two were the same at .015" which allowed me to use the same neck bushing(.292") in my full length dye. Headspace(-.002") was also the same with that dye. The Norma case bodies were thicker at 5gr heavier in weight compared to the Lapua brass(201gr) and, the Lapua brass capable of approximately +2gr of Retumbo before compression. However, with a charge weight of 57gr, and the same seating depth(.075" OL), velocity, accuracy, and ES were quite close. While, at the time, I chose to maintain my velocity of 2965FPS. Using the same bullet seating depth, I could increase my charge weight using Lapua brass as much as 2gr of Retumbo(mild compression) for a velocity increase of 50FPS. My Norma/Nosler brass information is about 10 years old, and I have not worked with recent lots. My Lapua brass information spans +10 years, and I have seen no variation in case dimension over this period
If I were the OP, I would do a similar comparison of the Nosler and Lapua case dimension/capacity and, to be be safe, do a load work-up starting a couple of grains less then his current Nosler brass load. With all likelihood, current results should be able to be duplicated with the Lapua brass. IMO