I bought a bunch of those 400 grain speer slugs for my 475L. Shot a few of them, but ended up settling on some of those cast hollow points from Dick Thompson. I need to find those speer bullets and post them for sale. I'll never use them.
Brenden, I've been shopping for them so PM me with a price. I may be interested!
At the same time, curious why you chose not to use them if you want to share...