I've been playing with some loads for a couple of my BP cartridge guns, one of them being a BP .500 express. I've found it so far to be very reliable and consistent. I would stress to you that you follow their load guide to the letter though as BH 209 is a bit more powerful than regular BP. Here is their loading guide for BP cartridges. http://www.blackhorn209.com/wp-conte...tridgedata.pdf