OzFclass

Well so much for summer.

Temps never got above 22 c but a wind chill of -2 kept things distinctly cool. Everything was fine, with no problems, but I have some loads I will keep till summer returns - hope fully soon.

I am no reloading genius, but have you looked at using heavier or lighter cases to "cheat" with pressure?

For example, with my TR in 308, I used Lapua brass with 46 grains 2208 (no surprises there , but when using Winchester brass (backups for long comps), I was using 47 grains for a similar outcome. Both powder quantities measured to the bottom of the neck, where the bullet base ends.

Had no chrono but elevation was within 2 minutes at 800y for the different cases.

Lapuas 170 grains (lot all within 0.2 grains), Winchesters (weighed lot) 161.5 grains. Never any signs of pressure.

My mate uses a 243 and does a lot of mucking around with loads. He says the PMC brass is heavy, and the Winchesters seem light.

Well the pressure problem has been solved! I have two batches of 2209. MEM 4522 & MEM 4387.
4522 appears to be at least 10% FASTER than 4387.

Dropped loads with 4522 and everything (pressure-wise) back to normal.

Glad to hear your issue has resolved itself.