I posted a comment about fire forming in the garage. I thought of my now deceased good buddy who had a 1950’s era technique for finding a max load. Increase powder until a primer blows or falls out then decrease by 1/2 grain.
He was one of the guys who added sand to cream of wheat to more fully form cases.
He got a chronograph and developed a new technique. He loved numbers and decided a 22” barreled 270W should move a 130 partition along at a minimum of 3200 so he added powder until he got that velocity. Then he shot 3 or 4 rounds and if the primers didn’t fall out he was good to go.
Really great guy who was loads of fun. But one day he asked my why I always stood behind him slightly to his left, he was right handed. I explained that I wanted his thick skull between me and his rifle’s receiver. He said I was a pussy.
A former high volume poster here used a similar method. I watched him shoot at a coyote with his 257 Wby, then clamp it between his legs so he could use both hands to pry the bolt open. He beat the ball of his hand black and blue driving the bolt back once he got it turned. Once the seized case was extracted he proudly exclaimed, "I guess I need to back that load off a quarter grain."
