New here. I don't think itll let me post pictures, but did some testing for grins this evening. Ive had a box of sierra pro hunter .338 300gr bullets for a while now and decided to mess with them in my 338 fed. I dont have quicklaod so if someone reading this wants to get velocity numbers for me that'd be cool.

I was finding max charge with Accurate 1680.
Started at 18.5gr to 25gr
Cci #250 Magnum large rifle primers (its what i had handy)
.338 Sierra pro hunter 300gr
Coal was 2.800"

18.5gr no sign
21.0gr no sign
23.5gr very slight flattening
24.0gr little bit more flattened
24.5gr little bit more flattened still
25gr starting to flow the primer into the firing pin hole
Thats where i stopped with it.

Like i said i dont have any velocity numbers so for what its worth heres my random bit of useless testing for the evening.