Yes some loads where slighty compressed, and I gonna to complete my message with those data too. I have also tried Varget powder and I didn´t got more than 2130 fp/s out from Their maxload 74 grains, and that was compressed and showed more signs on pressure than any loads of Accurate 2520.

I don´t think that anyone need more than 2100 fp/s out from a 458 with a 500 grains bullet. My rifle weight is 8 pounds and there is a lot of recoil when I going up to 2200 fp/s. Now I have increase my rifles weight to 9 pounds with lead in the stock, but there is a lot of recoil with those loads anyway.

If I load my 458 Lott I get 200 to 300 fp/s more out at the same pressure as my 458 WM, but I don´t think that the animal gonna to die faster anyway. My goal is to reach 2100 to 2150 fp/s out from my 458 WM with a 500 grains bullet, not to reach highest velocity possible.