Also, the 777 and cleanbore primers are nice and clean, but they can leave up to40 fps(average around 25fps)off your velocity. A hotter 209 primer can give a small, but noticable increase in your velocity. Federal 209a primers are the hottest widely available primer, but they are not nearly as clean as the primers designed for bp subs. The orange mmp's are sabots for .458" bullets in a .50 bore. The black crush rib sabots are designed to be a easy loading sabot with .452" bullets, but work very well in my rifle with .458" bullets

http://www.mmpsabots.com/ for orange mmp sabots( price is delivered)
http://www.midsouthshooterssupply.com/item.asp?sku=00072H15045BR for black crush rib sabots(good price too)