What are they?

Barrel Extensions are devices to be inserted in the choke tube seat of your shotgun’s barrel sticking out 100 mm past the same. As for some specific models, 50 mm extensions are also manufactured. Their function therefore is, actually, to lengthen the shotgun barrel by 50mm or 100mm (or approx. 2" or 4").

Their characteristic is to be equipped in their terminal part, with the same choke seat of the shotgun, so as to be suitable to house any choke tube you want to install and use for your activities. Gemini Barrel Extensions can be easily combined with the choke tubes already supplied with your shotgun.

Recommended and not recommended for use

You can mount the Barrel Extensions to a self-loading hunting shotgun, while you can hardly install two Barrel Extensions on a superposed shotgun or on a side-by-side shotgun, for two simple reasons: first the interaxle spacing between the barrels may be inadequate, secondly the barrel convergence might be too strict thus making it impossible to use the two extensions simultaneously.

Avoid installing a Barrel Extensions into another (for instance 50 mm + 50 mm) to increase the length of your barrel, we also remind you that it is strongly advised against any extension of the shotgun barrel beyond 80 cm.

When to use an Extender? First of all, you will buy an Extender of +100 mm if the barrel of your shotgun is short (60-70 cm or 23.5-27.5") and you aim to medium long distance shooting. In the second place whereas the barrel of your shotgun is medium (70-75 cm or 27.5-29.5") and you aim at long distance shooting; specifically choose a +50 mm Extender if you have a 75 cm barrel shotgun and a +100 mm Extender if you have a 70 cm barrel shotgun.


All of the Barrel Extensions are made of 42CrMo4 alloy steel, coated with Nickel + DLC and are available in models for 12-, 20- and 28-gauge.


In order for the Extender to be light and easy to handle, it is made with the minimum thickness necessary so as to guarantee its efficiency, yet this precaution prevents the creation of slots for the tightening key. For this reason, you will have to manually mount and lock your Extender; its conformation actually offers an excellent grip and does not complicate this operation.

Maintenance and cleaning

Perform a normal cleaning, with the specific Gemini kit or an ultrasonic cleaning machine. Pay attention to the impacts, which might affect its integrity.

Originally published by Gemini Chokes, Blog, Guides: 06/21/2021