April 29th, 2018

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.

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 »
April 29th, 2018

Buchanan Hand Press Review by UltimateReloader.com

Buchanan Hand Press reloading level-action portable sizing die lee

Our friend Gavin Gear of UltimateReloader.com recently tested the nicely-crafted Buchanan Hand Press. This symmetrical, twin-lever tool can handle pretty much any sizing and/or seating task as it offers plenty of leverage — even for full-length case resizing. Crafted by Buchanan Precision Machine, this Hand Press has a central mount for the die on top with a conventional shell-holder at the bottom. There is a handy spent primer catcher, plus an optional Lock-N-Load die insert adapter. This press is well-built, but the $245.00 price is steep. You can buy FIVE Lee Hand Presses for the cost of this Buchanan.

You can see how this press works in this recent UltimateReloader video. Gavin demonstrates all the key functions, including decapping, sizing, and bullet seating. You can see that Gavin was impressed with this hand press, which is well-suited for loading at the range:

Gavin explains that the modern Buchanan Hand Press is based on a previous design: “This press is an evolution of an old press that has been out of production for years: the Huntington Industries Decker Hand Press. While it shares some of the basic design features, the Buchanan Precision Machine Hand Reloading Press takes quality and functionality to the next level. This press accepts standard shell holders, uses standard 7/8×14 dies (or dies with Hornady Lock-N-Load bushings as I showed in the above video), and has a COL capacity of 3 3/4″. Need to load 30-06 away from the bench? No problem, this press can handle it. Unlike other hand presses, this one stands by itself on a flat/level surface, and can be clamped to a bench in order to stay in one spot.”

Buchanan Hand Press reloading level-action portable sizing die lee

For more details, check out the full Buchanan Precision Hand Press Review on UltimateReloader.com.

Permalink Gear Review, New Product, Reloading 7 Comments »
April 29th, 2018

Hang Your Cleaning Rods with Fishing Rod Racks

Fishing Rod Rack Cleaning RodsForum member Nodak7mm has discovered an ideal way to store your rifle cleaning rods in your garage or loading room. Using inexpensive Berkley Horizontal Fishing Rod Racks, Nodak7mm has secured a half-dozen Dewey rods on the back of a door. You could also mount the racks along a wall or on the side of a storage cabinet. This installation takes up minimal space and the Berkley Racks cost just $9.96 per set at Walmart or $9.96 at Amazon. If you prefer wood, Amazon also sells a pine 6-rod wall rack for $24.85.

Nodak7mm explains: “I was moving some fishing poles around and ended up with an extra pair of Fishing Rod wall racks. I said to myself, ‘I bet this would hold my Dewey cleaning rods’. I mounted the pair on the inside of a closet door in my man cave and put my cleaning rods in it. It works like a charm and is far cheaper than a specially-made rack that only lets the rods hang. One can even slam the door with the rods mounted and they stay put. This rod rack set… is made by a nationally recognized name and does a great job of holding the cleaning rods securely and safely.” These are inexpensive and are easy to mount to a door or wood cabinet.

Stow Your Cleaning Rods on Your Gun Safe
Another option is to make a rod set with a magnetic backing strip. This can be affixed to the sides of your gun safe or steel storage cabinet. Here is a home-made, magnet-affixed cleaning rod holder made by Forum Member “BobM”. This smart installation works great. CLICK HERE for more information.

magnetic rack gun cleaning rod gun safe

Permalink Gear Review, Reloading 2 Comments »