378 Weatherby Mag

Warning: Bullet selections are specific, and loads are not valid with substitutions of different bullets of the same weight. Variations in bullet material and length will alter net case capacity,  pressure and velocity results. Primer selection is specific and primer types are not interchangeable. These data represents maximum loads in our firearms and test equipment and may easily be excessive in other applications. All loads should be reduced by 3%,  and developed following safe handloading practices as represented in established reloading manuals produced by component manufacturers. Presentation of these loads does not constitute a solicitation for their use, nor a recommendation.

 

Cartridge: 378 Weatherby Magnum

  Firearm: Weatherby Mark V Deluxe   Max COL: 3..655″ (SAAMI)
  Bullet Diameter: 0.375″   Primer: CCI 250 Large Rifle Magnum
  Barrel: 26″   Reloading Dies: Redding

  Max case length: 2.913″

  Group: Distance 100 yards – Three shots

 

COL and Capacity   Load Data & Performance
Bullet Type Bullet
Weight
C.O.L.
Inches
Net
Grains
Water
  Powder Charge
Grains
Muzzle
Velocity
FPS
Muzzle
Energy
Ft/Lbs
Group
Size”
Barnes TSX 235 3.630 121.8   Re22 117.0 3317 5741 0.9
Barnes TSX 235 3.630 121.8 H4831 114.0 3219 5408 0.8
Barnes TSX 235 3.630 121.8 IMR 7828 117.0 3324 5767 0.9
Swift A-Frame 250 3.645 126.6 AA MagPro 124.0 3220 5757 1.2
Swift A-Frame 250 3.645 126.6 Re22 118.0 3253 5876 1.1
Swift A-Frame 250 3.645 126.6 IMR 7828 118.0 3226 5779 0.8
Swift A-Frame 270 3.645 123.6 AA MagPro 120.0 3064 5630 1.1
Swift A-Frame 270 3.645 123.6 Re22 114.0 3133* 5886 0.9
Swift A-Frame 270 3.645 123.6 RS Magnum 123.0 3133* 5886 1.2
Speer GR-GS 285 3.635 122.9 AA MagPro 120.0 3124 6175 1.2
Speer GR-GS 285 3.635 122.9 Re22 114.0 3096 6067 1.2
Speer GR-GS 285 3.635 122.9 H1000 120.0 3057 5915 1.3
Swift A-Frame 300 3.645 121.8 AA MagPro 116.0 2996 5979 0.9
Swift A-Frame 300 3.645 121.8 Re25 115.0 3019 5994 1.0
Swift A-Frame 300 3.645 121.8 H1000 118.0 2983 5927 1.2
Sierra SPBT 300 3.655 120.5 AA MagPro 117.0 3022 6084 1.0
Sierra SPBT 300 3.655 120.5 Re25 115.0 2998 5989 0.7
Sierra SPBT 300 3.655 120.5 IMR 7828 111.0 3003 6008 1.2
Woodleigh WCPP 350 3.655 118.4 AA MagPro 109.0 2769 5960 1.0
Woodleigh WCPP 350 3.655 118.4 H1000 113.0 2789 6044 1.3
Woodleigh WCPP 350 3.655 118.4 RS Magnum 114.0 2824 6196 1.2
* not a typo

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