Choke (firearms)

Briley Manufacturing, one maker of interchangeable shotgun chokes, uses a conical portion about 3 times the bore diameter in length, so that the shot is gradually squeezed down with minimal deformation.

For shooting most game birds and clay pigeons, a desirable pattern is one that is as large as possible while being dense enough to ensure multiple hits on the target, at a particular range.

A skeet shooter shooting at close crossing targets might use 0.13 mm (0.005 in) of constriction to produce a 75 cm (30 in) diameter pattern at a distance of 20 m (22 yd).

A trap shooter shooting at distant targets traveling away from the gun might use 0.75 mm (0.030 in) of constriction to produce a 75 cm (30 in) diameter pattern at 35 m (38 yd).

Special chokes for turkey hunting, which requires long range shots at the small head and neck of the bird, can go as high as 1.5 mm (0.059 in).

As far back as 1787 a Frenchman by the name of M. Magne de Marolles gave an account of choke-boring, though he argued against it.

[3] Some sources state that the first pioneer was a Czech named Dominik Brandejs, who made shotguns with a choke in order to reduce the dispersion of shots, but his design was not popular in the 1820s.

Long, in his book American Wildfowling, credits Jeremiah Smith of Southfield, Rhode Island, as the gunsmith who first discovered the concept, as far back as 1827.

[5] The first known patents for choke boring were granted Sylvester H. Roper, an American inventor and gunsmith.

Hence, Greener had to conduct many experiments to determine the perfect shape and size of a choke for a given bore.

William Wellington Greener is thus widely credited as being the inventor of the first practical choke, as documented in his classic 1888 publication, The Gun and its Development.

The next issue came with an advertisement from Greener, stating that the firm would guarantee that their new guns would shoot a closer pattern than any other manufacturer.

The results of these trials were responsible for making the W.W. Greener name famous, and for confirming the practical advantage of a repeatable method of controlling the performance of a choke on a shotgun.

This gave a tighter shot pattern and a greater risk of missing, but ultimately led to his target falling faster to win the Shoot-Off.

Choke is measured experimentally by observing the percentage of pellets in a charge that impact inside a 75 cm circle at 35 m (25 m for "cylinder" and "Skeet").

Oval chokes, which are designed to provide a shot pattern wider than it is tall, are sometimes found on combat shotguns, primarily those of the Vietnam War era.

[12] Military versions of the Ithaca 37 with duckbill choke were used in limited numbers during the Vietnam War by US Navy Seals.

When a "jug choke" is implemented in an existing choked barrel, the bore inside the bored-out section of barrel effectively becomes "overbored", and this also typically lessens the amount of shot deformation, thereby increasing the shot pattern density.

Due to changing worldwide waterfowl hunting law restrictions, the use of lead shot has been banned in many parts of the world by international agreement.

[14][15] In the United States, UK, Canada, and many western European countries (France as of 2006), all shot used for waterfowl must now be non-toxic, and therefore may not contain any lead.

Other alternatives to lead shotshells than bismuth also exist that are legal for hunting waterfowl, and which are safe for use with older chokes.