E3 Enhanced Bolt

The E3 Enhanced Bolt from Knight’s Armament features a number of components designed to make this bolt the most durable and reliable bolt available. It is a proprietary bolt specifically designed for our SR15 and 16 models. The E3 Bolt boasts several features that add to the its overall performance such as the enlarged bolt face, rounded lugs, reduced cam pin, and proprietary extractor and firing pin designs.


This E3 Bolt is manufactured with an enlarged bolt face that provides more positive engagement in the chamber and lugs which are rounded to help to reduce chipping, cracking and snapping. This strengthened design helps to increase the life of the bolt and ensure a proper seating each time the weapon cycles.

The E3 Bolt’s extractor design is also a unique achievement that helps to provide an extremely reliable component. It’s shaped like a rounded ‘T’ and sometimes referred to as a ‘butterfly’ shape. The pivot point of the extractor is shifted forward to help balance out the extractor and apply constant pressure on the shell which reduces cases of extraction failures. Another strong feature of the unique design of this extractor is the use of two full size extractor springs, as opposed to the standard micro spring. This allows for a reduction of relative compression while the extractor is in motion and provides a failsafe in case one spring fails. The bolt will continue to function properly and afford a user the opportunity to continue with their mission or firing schedule.

The E3 Bolt is designed with a thinner Cam Pin and Firing Pin whose overall size has been reduced. The thinner Cam Pin allows for a thicker bolt web which is a common failure point in normal bolts. The reduction of the Firing Pin size is to accommodate the thinner Cam Pin.

The full capabilities of the E3 Bolt are realized when exposed to full auto or extremely high cyclic firing rates yet the bolt performs gracefully under casual firing conditions. This component was designed to be exposed to the most stressful and unrelenting conditions and exceed expectations for durability and service life.


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