Some interesting notes on 800-X. I just chronographed a load using 9.5 grs with a Remington 124/125 HP. It registered a 1400fps velocity out of my G33 with the stock barrel. I also ran some factory Buffalo Bore 124 gr loads and they averaged about 50fps slower than the 800-X loads.
The 800 loads seemed very stout to me and still IMR says max load is .5grs more. 10 grs max at only 36,100psi.
I'm not sure I even want to try 10 with the speed of the 9.5's