Although Nosler Premium Brass is weight sorted within lots, the difference between different lots is extraordinary.
I think the difference is large enough to cause pressure problems if you worked up loads for the lighter cases and then used that data in the next box of brass you bought at the same time. At least this is my experience.
I discovered this with different lots of Nosler Premium brass for the 270 Winchester all purchased since covid.
In two different 270 Winchester barrels, a Shilen Match and a Bartlein 5R, I noticed velocity that was about 100 FPS different for both the barrels. I was shooting my favorite load of 58g of H4831sc with 130 grain Sierra BTS and Nosler BTs. Both barrels were showing this huge velocity swing depending on the case lot (the Shilen barrel shot both velocities pretty well, the Bartlein shot the higher velocity extremely well and was grouping poorly with the lower velocity).The cases looked the same and were bought within a year of each other recently.
After weighing the cases I found the different lots were 31 grains difference, about 18%. One lot was 31 grains more than the lighter lot and the other was 30 grains. Curious, I weighed some other fired cases I had handy. I had WW 270 cases going back to the mid-80s up to covid. The WW weight difference of 5 different lots from that time span was 4 grains. Within lot weights was not as close in weight as Nosler, but the total 35 years in production was a fraction of the lot to lot difference experienced with the Nosler Premium. Federal 30-06 cases going back about 10 years was the same, about 4 grains total variance between lots. In 270, the Nosler was by far the lightest of any cases I weighed and also the heaviest. This test also included Federal and Estate 270 cases (where I didn't have enough different lots to do a meaningful lot to lot variance study).
This leads me to believe one needs to work up their load data for each new lot of Nosler Premium brass, even if bought at the same time, something I have never done in the past. I worked up new data if a new lot of powder, or a different primer or a new bullet, but never for brass, primers and bullets from different lots. Using my Garmin GPS is so convenient I use it for every bench shot and it is adding a new level of information to learn more about shooting.
I think the difference is large enough to cause pressure problems if you worked up loads for the lighter cases and then used that data in the next box of brass you bought at the same time. At least this is my experience.
I discovered this with different lots of Nosler Premium brass for the 270 Winchester all purchased since covid.
In two different 270 Winchester barrels, a Shilen Match and a Bartlein 5R, I noticed velocity that was about 100 FPS different for both the barrels. I was shooting my favorite load of 58g of H4831sc with 130 grain Sierra BTS and Nosler BTs. Both barrels were showing this huge velocity swing depending on the case lot (the Shilen barrel shot both velocities pretty well, the Bartlein shot the higher velocity extremely well and was grouping poorly with the lower velocity).The cases looked the same and were bought within a year of each other recently.
After weighing the cases I found the different lots were 31 grains difference, about 18%. One lot was 31 grains more than the lighter lot and the other was 30 grains. Curious, I weighed some other fired cases I had handy. I had WW 270 cases going back to the mid-80s up to covid. The WW weight difference of 5 different lots from that time span was 4 grains. Within lot weights was not as close in weight as Nosler, but the total 35 years in production was a fraction of the lot to lot difference experienced with the Nosler Premium. Federal 30-06 cases going back about 10 years was the same, about 4 grains total variance between lots. In 270, the Nosler was by far the lightest of any cases I weighed and also the heaviest. This test also included Federal and Estate 270 cases (where I didn't have enough different lots to do a meaningful lot to lot variance study).
This leads me to believe one needs to work up their load data for each new lot of Nosler Premium brass, even if bought at the same time, something I have never done in the past. I worked up new data if a new lot of powder, or a different primer or a new bullet, but never for brass, primers and bullets from different lots. Using my Garmin GPS is so convenient I use it for every bench shot and it is adding a new level of information to learn more about shooting.
