My results have also been very dismal. I have tried everything I can with 87 vmax, 95 NBT and 95 TMK. I have tried H335, Tac, 8208, Benchmark, Lever, H4895 and 3 different primers. I have tried 2.365” oal, modded my upper and lower to get to 2.400” and today even tried single loading the TMK at 2.500”. I got 1 single 3/4” 3 shot group a few weeks ago with the 95 nbt and Tac which I could not duplicate. I too have had to go way over book to get velocity but it won’t group at any charge. I would say 3-4” is the average 3 shot group, nothing worth going past 3 shots. I even swapped scopes today to a known good Trijicon. I basically have around 200 rounds of bang my head against the wall load development. I am seeing radially lines in my brass (mid body) and it looks like the same marks in the chamber like rough machining. A couple pieces of brass have split radially at those marks. Saami spec for the neck portion of the chamber should be .270”. A loaded round measures .265” and a fired case is .275-.276”! That’s a lot of growth and I am guessing that is why the brass is getting beat up and probably where the velocity loss is coming from. It also appears to have an extra long freebore. I will add my lengths below. At this point it is looking like an expensive tomato stake. At least it shouldn’t rust! It shouldn’t be the profile. My guess is an out of spec reamer, supposedly it was a saami reamer. The Shaw portless was in the 3/4 to 1 1/4” range consistently for 5 shots. No need for any cooling between shots or anything. Only needed to test the one bullet I wanted to use with it and tried 2 or 3 powders that all seemed to work.
Distance to lands
87 vmax 2.395” (tried 2.300, 2.365 and 2.385”)
90 NBT 2.415”
95 sst 2.386”
95 NBT 2.430”
95 TMK 2.580” (nearly falling out)
