I finally chronographed some loads for my .500 8 3/8" bbl.
These are 5 shot averages
350gr Sierra JHP, 15.5gr Titegroup, Federal Large pistol primer in Hornady brass- 1275 fps
400gr Sierra JSP, 36gr Lil' Gun, Federal Large Rifle Primer, Cor-Bon brass, -
1415 fps.
The 350gr load was...