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Vihtavuori updates .357 Magnum reloading data to SAAMI standard

June 18, 2026

Vihtavuori is updating all published .357 Magnum reloading data to align with the SAAMI maximum standard pressure of 35,000 PSI. This update follows our policy to publish the safe load limit, whichever is lower between C.I.P. and SAAMI specifications.

Previous .357 Magnum data was based on the C.I.P. maximum pressure of 3,000 bar, which is approximately 20 % higher than the updated SAAMI standard. To ensure reloading safety, all Vihtavuori .357 Magnum loads will now follow the SAAMI pressure limit.

The updated velocities have been measured using a Smith & Wesson M586 revolver with a 6” / 153 mm barrel.

In addition, this update includes several bullet options, featuring Lehigh Defense Extreme Defense, Hornady XTP, Magtech SJSP, Sierra JSP, Speer TMJ, and H&N TC HS.

“This reloading data update affects all Vihtavuori powders and bullet combinations listed for .357 Magnum. We strongly recommend that all reloaders review their existing loads and adjust them according to the new data, as older C.I.P.‑based maximum loads may exceed the new SAAMI pressure limits”, says Samppa Virtanen, Nammo Vihtavuori’s Chief of Test Shooting.

The updated .357 Magnum data is now available on both our website and the free Vihtavuori Reload App. As always, updated data lines are highlighted in orange for easy identification.

Vihtavuori is updating all published .357 Magnum reloading data to align with the SAAMI maximum standard pressure of 35,000 PSI. This update follows our policy to publish the safe load limit, whichever is lower between C.I.P. and SAAMI specifications. To ensure reloading safety, all Vihtavuori .357 Magnum loads will now follow the SAAMI pressure limit.