April 28th, 2020

Vihtavuori Explains Powder Grain Shapes

Vihtavuori loading propellant reloading powder N133 N150 N140 N550 ball flake stick extruded perforated powders

POWDER GRAIN SHAPES — What You Need to Know

The shape of powder grains has a profound effect on the performance of the powder charge, as it concerns both pressure and velocity. There are multiple powder shapes including flake, ball, and extruded or “stick” (both solid and perforated).

All Vihtavuori reloading powders are of the cylindrical, single-perforated extruded stick type. The differences in burning rate between the powders depend on the size of the grain, the wall thickness of the cylinder, the surface coating and the composition. Cylindrical extruded powders can also have multi-perforated grains. The most common types are the 7- and 19-perforated varieties. A multi-perforated powder grain is naturally of a much larger size than one with a single perforation, and is typically used for large caliber ammunition.

Other types of powder grain shapes include sphere or ball, and flake. The ball grains are typically used in automatic firearms but also in rifles and handguns. The ball grain is less costly to produce, as it is not pressed into shape like cylindrical grains. Flake shaped grains are typically used in shotgun loadings.

Vihtavuori loading propellant reloading powder N133 N150 N140 N550 ball flake stick extruded perforated powders

Web thickness in gunpowder terminology means the minimum distance that the combustion zones can travel within the powder grain without encountering each other. In spherical powders, this distance is the diameter of the “ball”; in flake powder it is the thickness of the flake; and in multi-perforated extruded powders it is the minimum distance (i.e. wall thickness) between the perforations.

The burning rate of powder composed of grains without any perforations or surface treatment is related to the surface area of the grain available for burning at any given pressure level. The change in the surface area that is burning during combustion is described by a so-called form function. If the surface area increases, the form function does likewise and its behavior is termed progressive. If the form function decreases, its behavior is said to be degressive. If the flame area remains constant throughout the combustion process, we describe it as “neutral” behavior.

The cylindrical, perforated powders are progressive; the burning rate increases as the surface area increases, and the pressure builds up slower, increasing until it reaches its peak and then collapses. Flake and ball grains are degressive; the total powder surface area and pressure are at their peak at ignition, decreasing as the combustion progresses.

So how does the shape affect pressure and muzzle velocity? In general, it can be said that powder that burns progressively achieves a desired muzzle velocity at lower maximum pressure than a powder that burns neutrally, not to mention a degressive powder. As grain size increases, the maximum pressure moves towards the muzzle, also increasing muzzle blast. Muzzle velocity and pressure can be adjusted by means of the amount of powder or loading density, i.e. the relationship between the powder mass and the volume available to it. As the loading density increases, maximum pressure grows.

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Vihtavuori loading propellant reloading powder N133 N150 N140 N550 ball flake stick extruded perforated powders


This article originally appeared on the Vihtavuori Website.

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July 29th, 2019

Jack Neary Shoots WBC Record 0.110″ at 200 Yards in Canada

Jack Neary Team Lapua Vihtavuori WBC World Championship benchrest 6mm PPC Calgary Alberta Canada

No, that’s not two shots — it is FIVE shots, with basically four in one hole and a fifth very slightly over. If that’s not impressive enough, consider this stunning 0.110″ group was shot at TWO HUNDRED yards — the length of two football fields. This amazing group was shot by Jack Neary at the 2019 World Benchrest Championship (WBC) held in Calgary, Alberta earlier this month.

Neary’s 0.110″ 200-yard group establishes a new WBC world record in the Light Varmint (LV) rifle class (10.5-lb max rifle weight). Jack was competing with Team USA “C Squad”, which also captured the WBC 2-Gun Gold Medal in the 4-man Team Championship.

Jack Neary Team Lapua Vihtavuori WBC World Championships benchrest 6mm PPC Calgary Alberta CanadaWorld Benchrest Championships
The World Benchrest Championships are held every two years and attract competitors from over 20 countries. Jack Neary’s .110″ group is now a confirmed WBC 200-yard World Record for smallest 5-shot group. Neary was shooting a 6mm PPC hand-loaded with Vihtavuori N133 powder.

NOTE: This is a record for WBC competition. However, it is slightly larger than current NBRSA and IBS 200-yard Light Varmint (LV) records. The NBRSA LV 200-yard record is 0.075″ set by Johnnie Stewart in 2009. The IBS LV 200-yard record is 0.091″ by David Farrar in 2006. Still, Neary’s 0.110″ 5-shot group is a great accomplishment, set at the highest level of competition, at a match which had very challenging conditions.

Jack Neary Team Lapua Vihtavuori WBC World Championships benchrest 6mm PPC Calgary Alberta Canada

Jack stated, “Vihtavuori’s temperature stability and cleaning burning attributes have been instrumental for competitors to achieve world record accuracy in the furthest corners of the world.”

Vihtavuori powders (predominently N133) were used by nearly every competitor (over 90%) during the World Benchrest Championship. VV N133 continues to dominate the short-range benchrest game. Notably, Vihtavuori powders have also been successful in the Extreme Long Range game, with VV powders used by recent KO2M winners. The next World Benchrest Championship will be held in Fall of 2021 in South Africa.

Jack Neary Team Lapua Vihtavuori WBC World Championships benchrest 6mm PPC Calgary Alberta Canada

Neary Helps Team USA Win Gold at World Championship

Team Lapua’s Jack Neary, along with his Team USA “C Squad” teammates Harley Baker, Gary Bristow, and Jeff Graves, won the 4-Man Team Gold Medal at the 2019 World Benchrest Championship held in Calgary, Alberta, Canada this past week. Neary’s squad had the best overall Grand Aggregate, 0.2598, for the WBC combined 2-Gun Championship. Team USA “A Squad” took second place with a 0.2646 2-Gun Aggregate. CLICK HERE for WBC Team Championship Results.

All Team USA Gold Medalists used Lapua cartridge cases exclusively at the WBC. Lapua cartridge cases are known for superb quality of construction, using only the finest raw materials and superior annealing processes. Each case is machined to exacting dimensions. Lapua brass is renown for its superior consistency and longevity. The best brass also lasts the longest.

Neary stated, “Lapua cases are the foundation [for] our competition hand-loads[.] When competing at the highest levels against the most talented shooters in the world, we need the absolute best components available. There’s no doubt Lapua helped secure the Gold for Team USA.”

Lapua vihtavuori CapstoneAbout Lapua and Vihtavuori
Lapua produces the highest-quality small caliber cartridges and components for civilian and professional use. Vihtavuori is renowned for smokeless powders with superb lot-to-lot consistency that deliver superior accuracy Lapua and Vihtavuori are part of the Capstone Precision Group, exclusive U.S. distributor for Berger, Lapua, Vihtavuori and SK-Rimfire products. For more information, visit Lapua.com and Vihtavuori.com.

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September 16th, 2016

Vihtavuori Powders Loading Information Online

vihtavuori reloading guide
Click image for Online Reloading Data. CLICK HERE for Printable PDF Reloading Guide.

Vihtavuori has updated and enhanced its reloading information, adding VV powder load recipes for many more cartridge types. Data is now online for 64 rifle cartridge types and 26 pistol cartridge types. You’ll find the updated reloading data on the Vihtavuori Website. Bookmark this link: www.vihtavuori.com/en/reloading-data/about-reloading.html.

The updated online information supplements the Vihtavuori Reloading Guide (2016 Edition) available in PDF format. The online Reloading Database has dedicated sections for Rifle Cartridges, Pistol Cartridges, and Cowboy Action. There is also a handy, FREE Reload Mobile App for iOS and Android.


Rifle Reload DATA | Handgun Reload DATA| Mobile Reload App

vihtavuori reloading guide

Rifle Reloading Data

Vihtavuori’s Rifle Reloading Database is now very comprehensive. Many of the popular modern match cartridges such as the 6.5×47 Lapua and 6.5 Creedmoor are now included, and of course you’ll find the 6mm PPC, 6mmBR, and 6XC. (There is no .284 Win or 7mm RSAUM data unfortunately.) You will find recommended load recipes for all the following cartridges:

.204 Ruger
.221 Remington Fireball
.222 Remington
.22 Hornet
.22 PPC-USA
.223 Remington
.22-250 Remington
.223 WSSM
.243 Winchester
.243 WSSM
6mm PPC-USA
6mmBR Norma
6 XC
6mm Remington
.240 Weatherby Magnum
6.5 Grendel
6.5 x 47 Lapua
6.5 Creedmoor
6,5 x 55 Swedish Mauser
6,5 x 55 Swedish Mauser/ SKAN
6.5-284 Norma
.25-06 Remington
.260 Remington
.270 Winchester
.270 WSM
.270 Weatherby Magnum
7 mm-08 Remington
7 x 57
7 x 64
7 mm Remington Magnum
7 mm WSM
7 mm RUM

7 x 57R
7 mm Weatherby Magnum
7,5 x 55 Swiss GP31
.30 Carbine
.30-30 Winchester
.300 AAC Blackout
7,62 x 39
.300 Savage
7,62 x 53R (7,62 Russian)
.308 Winchester
.30-06 Springfield
.300 Lapua Magnum
.300 Remington Ultra Magnum
.300 Winchester Magnum
.300 Weatherby Magnum
.30-.378 Weatherby Magnum
.300 H&H Magnum
.300 WSM
.303 British
8 x 57 IRS
8 x 57 IS (8 mm Mauser)
.338 Winchester Magnum
.338 Lapua Magnum
9,3 x 62
9,3 x 66 Sako
9,3 x 74R
.375 H&H Magnum
.416 Rigby
.444 Marlin
.45-70 Government
.458 Winchester Magnum
.50 Browning

Handgun Reloading Data

Likewise, VV’s Handgun Reloading Database is extensive. These pistol cartridges are covered:

.32 S&W Long N.P.
.32 S&W Long Wadcutter
.357 Remington Maximum
.357 Magnum
.357 SIG
.38 Super Lapua
.38 Super Auto
.38 Special
7 mm GJW
7 mm TCU
7 mm BR Remington
7,62 x 25 Tokarev
9 mm Luger

9 x 21
9 x 23 Winchester
.40 S&W
10 mm AUTO
.41 Remington Magnum
.44 S&W Special
.44 Remington Magnum
.45 ACP
.45 Colt
.45 Winchester Magnum
.454 Casull
.500 S&W Magnum
.50 AE

Story Tip by EdLongrange. We welcome reader submissions.
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December 8th, 2015

Point-Blank Powders in Stock — PVI Has Jugs of the Good Stuff

Vihtavuori N133 powder valley

Here’s good news for short-range benchrest shooters. The two most popular powders for the 6PPC, Vihtavuori N133 and Accurate LT-32, are now in-stock at Powder Valley Inc. (PVI). In fact, Powder Valley even has the hard-to-find 8-lb jugs of N133 and LT-32.

For you 30BR score shooters, PVI has both Hodgdon H4198 and Accurate LT-30 in stock, the two most popular powders for the 30BR. A slightly faster-burning version of LT-32, LT-30 is a very promising powder for the 30 BR, while H4198 has traditionally been the “go-to” choice for the 100/200-yard score shooting game. PVI has 1-lb and 8-lb containers of both these ultra-accurate powders in stock now. Visit PowderValleyinc.com, and click on the “Powders” link in the Menu.

6PPC Powders 30 BR Powders

– PVI has 1-pound LT-32 for $27.10
— PVI has 8-pound LT-32 for $204.30
— PVI has 1-pound N133 for $31.25
— PVI has 8-pound N133 for $202.00

– PVI has 1-lb LT-30 for $27.10
— PVI has 8-pound LT-32 for $204.30
— PVI has 1-pound H4198 for $23.25
— PVI has 8-pound H4198 for $165.00

Lapua Vihtavuori burn rate charts

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January 15th, 2015

Load Data for Accurate LT-30 and LT-32 Powders

Western Powders LT-32 LT-30 accurate powder

Is that target good enough? Yes that’s really five (5) shots. This amazing group was shot, in competition, with 6 PPC cartridges loaded with Accurate LT-32 powder. If you’d like to try out this powder in your rifle, Western Powders has released loading data for the LT series of powders. LT-32 is a good choice if you’re currently using propellants with burn rates similar to Vihtavuori N133 or Hodgdon Benchmark powders. (Caution: NEVER simply substitute loads powder for powder. Always start low and work up when trying a new powder). The other powder in Accurate’s LT series, LT-30, has a burn rate similar to Hodgdon H4198. LT-30 is a superb performer in the 30 BR cartridge. LT-30 also is a good choice for small varmint cartridges such as the 17 Rem Fireball.

Western Powders LT-32 LT-30 accurate powder

benchrest 30 BR rem remington lt-32 powder Western

Download FREE Reloading Guide for Accurate and Ramshot Powders
You can also download the complete Western Powders Reloading Guide in PDF format. This covers Accurate and Ramshot propellants.

Western Powders LT-32 LT-30 accurate powder

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January 20th, 2014

Nammo Announces Acquisition of Vihtavuori

Nammo Lapua acquires VihtavuoriIt’s official. Representatives of Lapua announced at SHOT Show 2014 that Nammo has purchased Vihtavuori, acquiring the “VV” line of propellants, and, most importantly, taking over Vihtavuori’s powder production facility in Vihtavuori, Finland.

This means that Vihtavuori is now officially under the Nammo umbrella as is Lapua, producer of brass, bullets, and loaded ammunition. Lapua engineer Tommi Tuuri has visited the Vihtavuori plant in person. Tommi says all operations are going well and the plant is running at normal capacity (but Nammo does plan some upgrades in the months ahead). Vihtavuori powders will continue to be imported into the United States as before and the powders will be made available through existing distribution channels.

Learn More about Nammo Purchase of Vihtavuori Powder Factory


The Vihtavuori Powder factory is located in Vihtavuori, Finland. Click marker to zoom.

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August 2nd, 2009

Tony Boyer Shares Secrets in PS Interview — READ IT!

Tony Boyer Benchrest InterviewTony Boyer is, without question, the greatest short-range Benchrest for Group shooter who has ever lived. In a rare interview for the August 2009 issue of Precision Shooting magazine, Tony shares many of his “secrets of success” with his friend (and fellow benchrester) James Mock. James also interviews Tony’s wife Faye, a superb shooter in her own right.

This Boyer interview is now, for a limited time, available online. CLICK HERE to READ INTERVIEW. Every short-range and mid-range benchrest shooter should read this article word for word, at least twice. Tony reveals insights that may surprise you, and will certainly enlighten you. You may be surprised that Tony is now shooting a .268″ neck.

And in the article Tony challenges many commonly-held ideas. For example he doesn’t think vertical is mostly load-related: “Most shooters think that vertical groups are caused by too light a powder charge. This may be true, but more often than not, the rifle has more to do with this than the load. If the rifle is muzzle heavy, this can cause vertical. Also, the way the action is set in the stock can cause vertical as can handling problems…such as shouldering the rifle.”

Barrel Quality is All-Important
What is the main secret to Benchrest accuracy? Throughout the interview, Boyer stresses the importance of barrel quality. Tony can quickly identify barrels with winning potential. He has “developed a system that takes no more than 30 rounds to determine if it is going to shoot”. Tony needs that kind of efficiency because he burns through barrels very quickly: “Contrary to what many say, I rarely shoot a barrel more than 600 rounds in competition. I can remember only one barrel that exceeded 1200 rounds.”

When asked if there was one paramount “secret” he could share to help new shooters, Tony replied: “If you have the means, buy as many barrels as possible. A great barrel is the real secret of this game. There are barrels out there that shoot better than they should. They have been given the name ‘hummer’. I can assure you that they exist.”

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