Hi there. Kind of stumped here and hoping you can help me out. Working up a load for a 338 LM in a weatherby accumark. 1F lapua brass, cci 250 and H1000 with the 300gr OTM Berger. Loaded to 2.906" ogive which puts me 0.160 off the lands (3.066" ogive lands).
I started with 3 shots 81, 82.6 and 84.2 which chonographed 2343fps, 2356fps and 2394fps respectively. Berger calls for 81gr @ 2500fps and 85.2gr @ 2629fps so I know right there that isn't going to happen.
I'm not sure if you can read the charge weights on the picture I took but the charges top (orange targets) L to R are 85gr, 85.8gr, 86.6gr, 87.4gr, 88.2gr and 89gr.
The bottom target first 3 are foulers where I just "threw" powder that was ~85gr. Continuing from L to R 89.8gr, 90.6gr, 91.4gr, 92.2gr (I held 2moa low as I was concerned it would go off the top of the paper. I drew a line where center would have been uncorrected. The 92.2gr load chronographed 2691, 2686, 2684fps.
The primers on the 81gr and the 92.2gr load are BOTH flat and they look exactly the same. Brass is very easy to resize (barely touches the side of the brass, mostly shoulder and neck) and primer pockets are tight. I don't have any "pressure" signs to go by so not sure if I can keep going up.
I would also appreciate any feed back on nodes you see and perhaps some advice on what to do next for further load development.