458 Winchester Magnum

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Handload Data

Warning: Bullet selections are specific, and loads are not valid with substitutions of different bullets of the same weight. Variations in bullet length will alter net case capacity,  pressure and velocity. Primer selection is specific and primer types are not interchangeable. These are maximum loads in my firearms and may be excessive in others. All loads should be reduced by 5% as a starting point for development where cartridges have greater than 40 grains in capacity and 10% for cartridges with less than 40 grain capacity following safe handloading practices as represented in established mainstream reloading manuals. Presentation of these loads does not constitute a solicitation for their use, nor a recommendation.

 

Cartridge – 458 Winchester Magnum
Firearm Winchester Model 70
Barrel Length 24.00″
Min – Max Case Length 2.500″ +0.000″/-0.020″
Min – Max COL 3.280″ – 3.340″
Primer CCI 250
Bullet Diameter 0.4590″ +0.000″/-0.0030″
Reloading Dies Hornady
Bullet Type  Bullet Weight
Grains
Net H2O
Grains
Capacity
COL” Powder Type Powder Charge
Grains
Muzzle Velocity
fps
Muzzle Energy
ft/lbs
Hornady SPRN
350 75.6 2.950 H322 78.0 2615 5316
Hornady SPRN
350
75.6 2.950 RS X-Term 80.0 2508 4890
Hawk Precision 350 77.9 2.970 H322 77.0 2569 5130
Hawk Precision 350 77.9 2.970 RS X-Term 80.0 2464 4720
Swift A-Frame 400 77.9 3.220 H322 76.0 2446 5315
Swift A-Frame 400 77.9 3.220 RS X-Term 78.0 2397 5104
Hornady DGX 500 70.0 3.310 RS X-Term 72.0 2089 4846
Hornady SPRN
350
75.6
2.950
Trail Boss
22.5
1250
1215
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