Vihtavuori N350 Smokeless Gun Powder: Slow-Burning Magnum Handgun Powder for .357, .44 & .45 Cartridges

Vihtavuori N350 is a porous, single-base N300-series handgun powder and the slowest-burning powder in that series — slower than N310, N320, N330, N340, and even 3N37. It burns faster than classic big-bore magnum powders like Alliant 2400, Accurate No. 9, Hodgdon H110, and Winchester 296. Its slow burn rate makes it a top choice for generating heavy, top-end velocities and energies across a broad range of magnum pistol and revolver cartridges, and it’s also popular in practical/USPSA-style pistol shooting.

Built for Heavy Magnum Loads

Vihtavuori’s production process controls the full chain from nitrocellulose manufacture to final bottling, giving the consistent lot-to-lot performance reloaders have relied on for more than 85 years. As a porous powder at the slow end of the N300 handgun lineup, N350 is built to fill larger magnum cases and push heavier bullets to top-end velocities.

Application Versatility

N350 has official published load data for 9mm Luger, .357 SIG, .38 Super Auto, 9×23 Winchester, 10mm Auto, .40 S&W, .45 Automatic, .357 Magnum, .357 Remington Maximum, .41 Remington Magnum, .44 S&W Special, .44 Remington Magnum, .45 Colt, .45 Winchester Magnum, .454 Casull, and .38 Special. It’s especially popular for magnum revolver cartridges and full-power practical-shooting pistol loads. If you’re loading a slightly faster-burning powder for competition-focused 9mm major or similar loads, Vihtavuori 3N37 is worth comparing.

Load Development

Always use published, manufacturer-tested load data when developing loads with N350. Start at the published minimum charge and work up in small increments, weigh every charge on a calibrated scale, and chronograph each string to track velocity consistency. Keep primer brand, bullet lot, and brass lot constant during development, watch for pressure signs, and document charge weight, seating depth, primer, and chronograph results so successful loads can be reproduced.

Quick Specs

• Type: Porous single-base handgun powder, N300 series, slowest-burning powder in the N300 series, faster-burning than Alliant 2400 / Accurate No. 9 / H110 / Win296
• Manufacturer: Vihtavuori (Finland)
• Best for: .357 Magnum, .357 Rem Maximum, .41 Rem Mag, .44 Rem Mag, .45 Colt, .45 Win Magnum, .454 Casull, 10mm Auto, .38 Super Auto, and other heavy-recoil pistol/revolver cartridges
• Container sizes: 1 Lb, 4 Lb

Safety Reminders

Before loading, review a few important guidelines. Never exceed the loads displayed in your reloading guide. Never mix two powders together, regardless of type, brand, or source. Never substitute smokeless powder for Black Powder or any Black Powder substitute. Store N350 in its original, sealed container in a cool, dry, well-ventilated place away from sunlight and heat sources.

Vihtavuori N350 For Sale, In Stock

USReloadingPowder keeps Vihtavuori N350 Smokeless Gun Powder in stock for magnum handgun and practical-shooting reloaders. Browse the rest of our lineup on the Vihtavuori Powders category page.

FAQs

What cartridges is N350 best for? It has official published load data for a wide range of pistol and revolver cartridges, including .357 Magnum, .44 Remington Magnum, .45 Colt, .454 Casull, 10mm Auto, and .38 Super Auto, among others.

Is N350 really the slowest N300-series powder? Yes — Vihtavuori positions it as the slowest-burning powder in the N300 series, slower than N310, N320, N330, N340, and 3N37.

Can I use N350 for shotshell loads? Vihtavuori’s official shotshell load data does not include N350 — for shotshell reloading, Vihtavuori’s own published data covers N320, N340, 3N37, 3N38, and N105 instead.

How should I store it long-term? Keep it sealed in its original container, stored in a cool, dry, ventilated location away from heat and sunlight. Proper storage keeps powder stable for years.