My elk load uses 90 gr of BH 209! Killed one this year and last year with that load.

NO, you don't need 150 gr of any powder. If I used that much, I would be doing two things: waisting money and developing a bigger flinch. I would wager 95% of all shooters will shoot more accurately with 100 gr than 150 grains IN THE FIELD.

Anyone who says you NEED more than 100 gr of black powder equivalent to kill ANY contiental US game has taken one too many anabolic steroids. Heard of the 45-70? 45 caliber with 70 gr of blackpowder. How many buffalo died to the caliber?

Certain long bullets may require higher charges (higher velocity) for better accuracy, but for the most part you should be able to find an accurate load in the 90-110 gr range.

Why would you subject your shoulder to the extra jar and your pocketbook to the extra cost?