500 grains, The cartridge holder that I was talking about is in fact the boyt holder that you can get from cabelas as the other poster stated earlier. You can get them for the .470 N.E and I bought a ten round holder that I stretched out for my .500 by wetting the holder and then placing the shells in the holder. Unfortunately, I have left my holder back in Tanzania so I won't be able to post a picture. I will try to remember to bring it back at the end of October and if you still need a picture, I will attempt to post one then. All I can say is that they are relatively cheap and it works very well for me.

Hope that helps,
Wadeb