Good information John, thanks.
MT DD FAN...your friend might be right. While the two powders look different, they do produce some of the same types of velocities now.
My old Sierra book listed the 1680 loads as 400 FPS slower than Western lists theirs now.
My 17FB coppers fouls a bit....thats why I picked up a can of BLK. Thought it was worth a try.
