Hello gang. I'm new here so hello to all and thanks in advance for your help. I started loading years ago based on Layne Simpson's recommendation of 80 grains of IMR 7828 behind a 160 grain TSX. I fired 40-50 rounds with no problem. Rifle is an accumark with 26 inch Barrel.Fast forward a few years and everyone is saying that 77 grains is max. I recently reloaded a few rounds with a new lot of powder (without working up,I'm new to this and made a bad mistake) and with 80 grains had a sticky Bolt and a blown primer. I can't figure out what happened or why the thoughts have changed on the max load nowadays. Rifle was clean, still new,same ambient temperature, same seating depth,new brass used. How could what was safe in 2000 be too hot today???Any help is truly appreciated.