As an Amazon Associate, this site earns a commission from Amazon sales.











December 11th, 2020

TECH Tip: Powder Grain Shapes — What You Need to Know

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.

Learn More with FREE Vihtavuori Reloading APP »

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


This article originally appeared on the Vihtavuori Website.

Permalink Bullets, Brass, Ammo, Reloading, Tech Tip No Comments »
December 11th, 2020

New Nosler Reloading Guide #9 — Data for 101 Cartridge Types

Nosler reloading guide number 9 9th edition handbook book load data manual

Nosler has just released the Nosler Reloading Guide #9, the latest in a respected series of hardback Nosler load manuals. This 800-page guide covers 101 cartridge types. New in this edition you’ll find the popular 6mm Creedmoor, 6mm XC, 6.5 PRC, and 7.62×39, along with 20 Nosler, 22 Nosler, 24 Nosler, 27 Nosler and 33 Nosler. This new guide draws from thousands of hours in the Nosler Ballistic Lab, along with the experience of many respected experts.

The book is available right now for $24.99 at Grafs.com. In addition, much of the book’s latest load data is available for free on the Nosler.com online LOAD DATA Center. But to get ALL the data, PLUS the technical article, you’ll need to buy the book.

The Nosler Reloading Guide 9 Reloading Manual provides load data for 101 rifle and handgun cartridges with hundreds of new powder additions. A comprehensive data set for today’s reloader, this manual is current with every bullet that Nosler offers through 2020 from 17 caliber up to 458 caliber in the rifle section and 9mm up to 45 caliber in the handgun section. Nine new cartridges were added to this manual. These include: 20 Nosler, 22 Nosler, 24 Nosler, 6mm Creedmoor, 6mm XC, 6.5 PRC, 27 Nosler, 7.62×39 and 33 Nosler. Also new for the Nosler Reloading Guide #9 are cartridge introductions written by veteran outdoor writers and industry tech experts. The 800-page book also has helpful “how-to” sections such as “Getting Ready to Reload”.

Nosler reloading guide number 9 9th edition handbook book load data manual
Nosler reloading guide number 9 9th edition handbook book load data manual

Q. Why Buy a Book when Load Data is Available Online from Powder Makers?

There are good, solid reasons to buy print-format loading guides produced by bullet-makers. If you go to the Hodgdon online Reloading Data Center you’ll only find loads with Hodgdon, IMR, and Winchester powders — the key brands they sell. In a book such as this Nosler #9 or the Sierra Reloading Manual, you will find loads with a much wider selection of powders including Vihtavuori, Alliant, Accurate, Norma, Ramshot, and other brands. You won’t find a Reloder 16 or VV N140 load on Hodgdon’s website.

In addition, it is handy to have loads in a print edition which is easy to access on your load bench. You don’t need a computer or an internet connection. And using a book is often faster than a web interface when quickly scanning through a variety of bullet choices for a cartridge.

Along with the new Nosler #9 Manual, here are four other recommended Reloading Manuals:

Permalink - Articles, New Product, Reloading 2 Comments »
December 11th, 2020

Lyman Remote Control Auto-Advance Target System

Lyman auto-advance target frame stand roll bullseye rimfire system

Lyman’s Auto Advance Target System is an innovative product for rimfire shooters. Shoot more, with less time wasted changing targets. The Auto Advance features a motor-driven roll of targets that can be “refreshed” with a radio remote-control. Here’s how it works — a 50-foot-long target roll is mounted in the top on the target stand. When you’re ready for a new target, push a button and a fresh target rolls into place. The radio remote-control activates a battery-powered electric motor that conveniently rolls a new target into place after the current target is shot out. The remote-control works at distances up to 200 yards. NOTE: This target system is rated for rimfire and air rifle use only — no centerfire.

There are currently four (4) target roll options: Five Bullseye Target, 11-Bull Smallbore Target, Silhouette Target, and Varmint Target. MSRP is $149.95; street price is currently $112.99 on Amazon.

This helpful Lyman video shows all the features of the Auto Advance, with instructions for frame assembly, target-roll loading/removal, and use of the remote control.

Lyman states: “The new Lyman Auto-Advance Target System offers shooters the ability to change targets at up to 200 yards with the press of a button! No more walking downrange to replace targets, or waiting for cease-fires! The Auto-Advance Target System is battery-operated, so there is no need for wires and power outlets, plus it disassembles easily for transportation back and forth to the range. The Auto-Advance Target System has steel protection plates that are rated for use with all rimfire calibers. The Auto-Advance Target System comes with a roll of standard bullseye targets. Additional 50-foot target rolls are available with bullseye, animal and silhouette designs.”

Lyman auto-advance target frame stand roll bullseye rimfire system

Permalink - Videos, Gear Review, Shooting Skills No Comments »