Polygonal Rifling

Enfield – a name that conjures memories of an old, rimmed rifle cartridge and the youthful exuberance of a first rifle. But to most, Enfield means rifling.

Enfield rifling is a traditional rifling pattern consisting of lands and grooves combined in a “square” pattern that twists along the barrel. Polygonal rifling gets rid of the boxes (and edges altogether) and resembles an octagon or hexagon (depending on the caliber and style).

Polygonal rifling has been around since the early days of rifled firearms but lost popularity right after the introduction of cordite. This was mainly due to the relatively soft metals being used in rifle barrels at the time.

However, it has seen resurgence. My Glock sports polygonal rifling. Several other pistol manufacturers use it as well. However, with a few notable exceptions, I have not seen polygonal rifling used in rifles – especially AR-style rifles. That is until now. Black Hole Weaponry, a manufacturer of barrels designed for the AR-style firearm has shed the traditional Enfield rifling in favor of the polygonal variety. Why? Several advantages have circulated their way around the internet. The most practical reason is a better gas seal around the bullet which leads to greater velocity and often improved accuracy. Also, due to its hill and valley design, there are no ridges or sharp areas to scrape copper from the bullet which leads to a reduction in fouling and longer barrel life.

Granted, other AR barrel makers offer polygonal rifling. Usually though, these more closely resemble Enfield rifling with rounded corners. This is not a true polygonal rifling pattern.

Do you need polygonal rifling? Nope, but variation is the spice of life, so I’m going to get one and try it out. I’ll let you know how what I think.

http://www.scienceofthehunt.com

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Tags: AR, polygonal, rifling

Category: Dr Shawley's Blog