I have found WW ball powders to be very sensitive to temperature changes. Especially going from cool to hot. I had an accurate load worked up with a WW ball powder in my 300 Win Mag. No signs of pressure and listed in reloading manuals. I took that load and rifle to the range. It was about 100 degrees Fahrenheit, maybe a little more.
The first round no signs of pressure. The bolt was sticky on the third round. The fourth round, I had to take the rifle back to the shop and pound/pry the empty case out of the bolt.
I walked to the target 100 yards away and back between shots to allow cooling and a consistent time between shots.
