GSP,
I copied/pasted the following from a thread I had years ago, when got my 450/400. Hope it helps at least a little.
Jeff
"Spent a little time at the range with the No.1 .450/400, and thought I'd pass on some data for some test loads. Bear in mind these were all samples of one 3-shot group of each load, as I merely wanted to get a rough idea if they were worth pursuing. Shot at 80 yards with a 3x scope off the bench.
All loads were with Hornady brass, and F215 primers.
400gr Hornady DGX w/ 65gr RL-15 w/Kynoch foam wad. 2043 fps Group size 1".
This load most closely approximated factory Hornady ammo, in my rifle. Within 10 fps, and identical POI.
400gr Hornady DGX w/65gr Big Game w/Kynoch foam wad. 1975 fps. Group size 1-1/2".
A little milder than RL-15. Should likely warm it up to match the RL-15 velocities to compare fairly, as it may not be working at a high enough pressure to be burning efficiently. Same POI as RL-15 & factory load.
400gr Hornady DGX w/86gr Magnum. No wad. 1955 fps. Group size 1".
POI was about 3" below factory ammo. Very accurate. Unfortunately, I doubt that much more powder can be added, as it was lightly compressed. Just thought that I'd give a really slow powder a try.
For fun, I tried the following light loads, and was really encouraged by the results. Again with Hornady brass, and F215 primers.
300gr Hornady flat nose w/58gr RL-15 w/Kynoch foam wad. 2057 fps. Group size 1".
Really pleasant to shoot, accurate, and POI was about 3" above factory. Would make a heck of a deer getter! Basically a mild .405 Win. Plan to vary the charge, and see if I can get the POI closer to factory.
300gr Hornady flat nose w/29gr Trail Boss and no wad. 1508 fps. Group size was 7/8"! Really mild load, with virtually no recoil, and quiet! POI was about 6-1/2" below factory. What a blast to shoot!
While not definitive, due to the small sample size, I hope the data will at least give you all some food for thought. Will post follow up loads when I get around to it, but that may be a while.
Jeff"
