Re: 300 WSM Loads (Rookie Alert)
Never use an internet load without reducing considerably, book loads also reduce 5%.
Rifles can vary considerably in the powder charge they will work with without excessive pressure. Especially custom rifles with long throats,etc.Even starting book loads in some may show pressure. Also, powder lots vary somewhat.
I would back down to 3 grains below the book at least and go up from there in 1g increments. Once you find some pressure back off 2% or more.
Keep in mind temperatures-loads developed at say 50 degrees may be dangerous at 80 degrees.