Load data for .338-378 Weath. Mag. + .338 | 250gr | Sierra SBT GameKing
Recommended Powder(s): ADI AR 2217, ADI AR 2225, Hodgdon H1000, Hodgdon Retumbo, Vihtavuori N565
Load Specifications
(Use the Personalized Load Calculator below to adjust )
Bullet: | .338 | 250gr | Sierra SBT GameKing |
Manufacturer SKU: | 2600 |
Bullet Weight: | 250gr | 16.2g |
Bullet Diameter: | 0.338" | 8.59mm |
Bullet Length: | 1.435" | 36.4mm |
Caliber: | .338-378 Weath. Mag. load data |
Case Length (l3): | 2.910" | 73.9mm |
Cartridge Length (C.O.L.): | 3.694" | 93.8mm |
Seated Depth: | 0.651" | 16.5mm |
Shank Seated Depth: | 0.461" | 11.7mm |
Case Capacity: | 137.0 Grains of Water | 8.90 cm³ |
Primer Size: | Large Rifle Magnum (LRM) |
Max. allowed Pressure: | 63817 psi | 4400 bar |
LID: | LID_B5928_C472 |
Last updated: | 2025-09-18 |
Recommended Twist Rate: | 1:14 - 1:12 |
Load data for 96 loads in caliber .338-378 Weath. Mag. with .338 | 250gr | Sierra SBT GameKing bullet and 48 powders such as ADI AR 2217, ADI AR 2225, Hodgdon H1000, Hodgdon Retumbo, Vihtavuori N565. The key underlying parameters are shown in the table above.
Important Notice: DO NOT go below Minimum Charge or above Maximum Charge unless there are reasons. Since xxlreloading.com has no control over the equipment and components used by the customer and the data used in connection with the website, any responsibility and liability for the results achieved is rejected. Also see our Terms of Service.
Questions regarding the load data: Please read the information in the next tab "Explanations".
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A load must fulfill certain criteria to be listed in the default view below - see "powder criteria to fulfill to be listed".
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Our load data might deviate from other sources - see the "most common reasons for deviations".
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All loads are based on the bullet and case dimensions shown under "Load Specifications" - see "reloading suggestions" if you deviate.
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You can set your specifications in the "Personalized Load Calculator".
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Use the Personalized Load Calculator to customize loads to your own specific requirements. Find more details in the help section.
Our default view only displays powders/loads that fulfill certain criteria: Max pressure of a load <=90% of Max. Standardized Pressure. Fill Rate (Min FR): >80% and <100% for rife loads, >60% and <100% for pistol loads. Min. Propellant Combustion (Min z): >90% for rifle loads , >80% for pistol/revolver loads. Relax these criteria at your own risk to potentially get more powders shown in the load tables.
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Click on the desired row in the tables below to add a specific load / powder to your Diary and manage there.
Powder | Charge | FR | MaxP | % | V(0) | z |
|---|---|---|---|---|---|---|
ADI AR 2209 | <<locked>> | 86% | 57392 | 90% | **12 | 100% |
ADI AR 2213 | <<locked>> | 88% | 56956 | 89% | **48 | 100% |
ADI AR 2217 👍 | <<locked>> | 97% | 56840 | 89% | **44 | 100% |
ADI AR 2218 | <<locked>> | 97% | 49240 | 77% | **08 | 97% |
ADI AR 2225 👍 | <<locked>> | 97% | 51866 | 81% | **08 | 100% |
Accurate 3100 | <<locked>> | 88% | 57043 | 89% | **40 | 100% |
[Accurate 8700]* | <<locked>> | 97% | 39059 | 61% | **23 | 92% |
Accurate MAGPRO | <<locked>> | 88% | 57392 | 90% | **61 | 99% |
Alliant Reloder-19 | <<locked>> | 86% | 57000 | 89% | **05 | 100% |
Alliant Reloder-22 | <<locked>> | 88% | 57392 | 90% | **41 | 100% |
Alliant Reloder-23 | <<locked>> | 89% | 57145 | 90% | **69 | 100% |
Alliant Reloder-25 | <<locked>> | 93% | 57043 | 89% | **38 | 100% |
Alliant Reloder-26 | <<locked>> | 85% | 57232 | 90% | **48 | 100% |
Alliant Reloder-33 | <<locked>> | 97% | 54259 | 85% | **61 | 98% |
Alliant Reloder-50 | <<locked>> | 97% | 46383 | 73% | **20 | 95% |
Hodgdon H1000 👍 | <<locked>> | 97% | 56840 | 89% | **44 | 100% |
Hodgdon H4350 | <<locked>> | 84% | 57188 | 90% | **56 | 100% |
Hodgdon H4831 | <<locked>> | 91% | 57058 | 89% | **95 | 100% |
Hodgdon H4831 SC | <<locked>> | 87% | 57290 | 90% | **02 | 100% |
Hodgdon Hybrid 100V | <<locked>> | 83% | 57072 | 89% | **17 | 100% |
Hodgdon Retumbo 👍 | <<locked>> | 97% | 51866 | 81% | **08 | 100% |
Hodgdon TrailBoss | <<locked>> | 96% | 36027 | 56% | **36 | 100% |
IMR 4831 | <<locked>> | 85% | 57159 | 90% | **46 | 100% |
IMR 4955 Enduron | <<locked>> | 89% | 57246 | 90% | **66 | 100% |
IMR 7828 SSC | <<locked>> | 87% | 57058 | 89% | **58 | 100% |
IMR 7977 Enduron | <<locked>> | 93% | 57072 | 89% | **40 | 95% |
IMR 8133 Enduron | <<locked>> | 97% | 47529 | 74% | **26 | 99% |
[Lovex D100]* | <<locked>> | 97% | 56405 | 88% | **66 | 94% |
Lovex S071 | <<locked>> | 93% | 56782 | 89% | **43 | 100% |
Norma 217 | <<locked>> | 97% | 48356 | 76% | **46 | 100% |
Norma MRP | <<locked>> | 86% | 57058 | 89% | **48 | 100% |
Ramshot Magnum | <<locked>> | 89% | 57116 | 90% | **18 | 100% |
ReloadSwiss RS 14 | <<locked>> | 97% | 37246 | 58% | **81 | 100% |
ReloadSwiss RS 76 | <<locked>> | 93% | 57421 | 90% | **20 | 100% |
ReloadSwiss RS 80 | <<locked>> | 96% | 57261 | 90% | **97 | 100% |
Rottweil R 904 | <<locked>> | 85% | 57043 | 89% | **72 | 100% |
Rottweil R 905 | <<locked>> | 86% | 57363 | 90% | **08 | 100% |
[SNPE Vectan SP 13]* | <<locked>> | 97% | 40828 | 64% | **46 | 93% |
Somchem S361 | <<locked>> | 84% | 57043 | 89% | **46 | 100% |
Somchem S385 | <<locked>> | 86% | 57392 | 90% | **66 | 100% |
Vihtavuori N165 | <<locked>> | 91% | 57406 | 90% | **59 | 100% |
Vihtavuori N170 | <<locked>> | 97% | 52765 | 83% | **20 | 96% |
Vihtavuori N555 | <<locked>> | 86% | 57435 | 90% | **76 | 100% |
Vihtavuori N560 | <<locked>> | 88% | 57276 | 90% | **61 | 100% |
Vihtavuori N565 👍 | <<locked>> | 92% | 57000 | 89% | **41 | 100% |
Vihtavuori N568 | <<locked>> | 95% | 57392 | 90% | **87 | 99% |
Vihtavuori N570 | <<locked>> | 96% | 56985 | 89% | **20 | 98% |
Winchester StaBALL HD | <<locked>> | 89% | 57290 | 90% | **58 | 100% |
Max Load - Barrel Length: 23.60''
Powder | Charge | FR | MaxP | % | V(0) | z |
|---|---|---|---|---|---|---|
ADI AR 2209 | <<locked>> | 81% | 49226 | 77% | **90 | 100% |
ADI AR 2213 | <<locked>> | 81% | 44324 | 69% | **31 | 98% |
ADI AR 2217 | <<locked>> | 81% | 32996 | 52% | **79 | 95% |
[ADI AR 2218]* | <<locked>> | 88% | 35520 | 56% | **97 | 90% |
ADI AR 2225 | <<locked>> | 81% | 30197 | 47% | **49 | 97% |
Accurate 3100 | <<locked>> | 81% | 45092 | 71% | **56 | 100% |
[Accurate 8700]* | <<locked>> | 94% | 35346 | 55% | **38 | 90% |
Accurate MAGPRO | <<locked>> | 81% | 44208 | 69% | **38 | 97% |
Alliant Reloder-19 | <<locked>> | 81% | 49139 | 77% | **80 | 100% |
Alliant Reloder-22 | <<locked>> | 81% | 45107 | 71% | **41 | 99% |
Alliant Reloder-23 | <<locked>> | 81% | 43758 | 69% | **69 | 100% |
Alliant Reloder-25 | <<locked>> | 81% | 37811 | 59% | **13 | 100% |
Alliant Reloder-26 | <<locked>> | 81% | 49516 | 78% | **36 | 100% |
[Alliant Reloder-33]* | <<locked>> | 84% | 33881 | 53% | **48 | 90% |
[Alliant Reloder-50]* | <<locked>> | 89% | 34911 | 55% | **70 | 90% |
Hodgdon H1000 | <<locked>> | 81% | 32996 | 52% | **79 | 95% |
Hodgdon H4350 | <<locked>> | 81% | 52460 | 82% | **77 | 100% |
Hodgdon H4831 | <<locked>> | 81% | 41524 | 65% | **30 | 97% |
Hodgdon H4831 SC | <<locked>> | 81% | 46166 | 72% | **12 | 98% |
Hodgdon Hybrid 100V | <<locked>> | 81% | 53055 | 83% | **57 | 100% |
Hodgdon Retumbo | <<locked>> | 81% | 30197 | 47% | **49 | 97% |
Hodgdon TrailBoss | <<locked>> | 87% | 31473 | 49% | **44 | 100% |
IMR 4831 | <<locked>> | 81% | 50502 | 79% | **48 | 100% |
IMR 4955 Enduron | <<locked>> | 81% | 45411 | 71% | **72 | 98% |
IMR 7828 SSC | <<locked>> | 81% | 45905 | 72% | **67 | 99% |
[IMR 7977 Enduron]* | <<locked>> | 83% | 41147 | 64% | **54 | 90% |
[IMR 8133 Enduron]* | <<locked>> | 81% | 27746 | 43% | **64 | 91% |
[Lovex D100]* | <<locked>> | 90% | 44701 | 70% | **66 | 90% |
Lovex S071 | <<locked>> | 81% | 38696 | 61% | **38 | 100% |
Norma 217 | <<locked>> | 81% | 27876 | 44% | **90 | 95% |
Norma MRP | <<locked>> | 81% | 48037 | 75% | **10 | 100% |
Ramshot Magnum | <<locked>> | 81% | 42815 | 67% | **85 | 99% |
ReloadSwiss RS 14 | <<locked>> | 83% | 30400 | 48% | **44 | 100% |
ReloadSwiss RS 76 | <<locked>> | 81% | 36172 | 57% | **36 | 99% |
[ReloadSwiss RS 80]* | <<locked>> | 81% | 33054 | 52% | **28 | 93% |
Rottweil R 904 | <<locked>> | 81% | 49864 | 78% | **57 | 99% |
Rottweil R 905 | <<locked>> | 81% | 48762 | 76% | **71 | 100% |
[SNPE Vectan SP 13]* | <<locked>> | 92% | 35288 | 55% | **21 | 90% |
Somchem S361 | <<locked>> | 81% | 51068 | 80% | **54 | 99% |
Somchem S385 | <<locked>> | 81% | 49139 | 77% | **48 | 100% |
Vihtavuori N165 | <<locked>> | 81% | 41684 | 65% | **03 | 99% |
[Vihtavuori N170]* | <<locked>> | 85% | 36434 | 57% | **05 | 90% |
Vihtavuori N555 | <<locked>> | 81% | 48588 | 76% | **51 | 100% |
Vihtavuori N560 | <<locked>> | 81% | 45339 | 71% | **64 | 98% |
Vihtavuori N565 | <<locked>> | 81% | 39566 | 62% | **26 | 97% |
[Vihtavuori N568]* | <<locked>> | 81% | 34432 | 54% | **51 | 93% |
[Vihtavuori N570]* | <<locked>> | 82% | 34403 | 54% | **64 | 90% |
Winchester StaBALL HD | <<locked>> | 81% | 42134 | 66% | **38 | 100% |
Start Load - Barrel Length: 23.60''
Any powder missing? Then click here.
FR ... fill rate of the cartridge in percent
MaxP ... max. pressure of load in psi or bar
% ... max. pressure of load in percent of the maximum allowed pressure for this caliber
V(0) ... muzzle velocity in feet per second (fps) or meters per second (m/s)
z ... powder burnt in percent
[...] *... not dangerous but load has suboptimal powder burnt with possible characteristics such as extensive muzzle flash or inaccurate loads.
[...] ²... fill rate low - you might want to consider using a filler to ensure proper ignition.
[...] ᴾ... possible press load - work up slowly to this load while watching for signs of excessive pressure.
👍 ... recommended powder/load for this caliber and bullet combination based on its ballistic performance.
<<locked>>... you need to buy an access license to unlock the data