In breech-loading firearms, a bolt is used to block the breech while the propellant burns inside the weapon’s chamber. Moving the bolt back and forth facilitates the loading and unloading of cartridges into the chamber from the magazine. Bolt designs vary based on the firearm type, but they generally contain the same basic parts, such as an extractor and a firing pin.


Brinkman Defense’s Bolt Project

The Fairchild Republic A-10 Thunderbolt II—an aircraft more commonly known among military service members as the A-10 Warthog—has seen combat action in every major U.S. military conflict since the Vietnam Era. The Warthog typically provides close air support to ground troops engaged in combat operations.

While the A-10 is not as common as it once was, there are still about 350 Warthogs in active service today. With continuing design modifications, some estimates predict that the A-10 will continue serving the U.S. military until at least 2040.

The A-10’s primary weapon is a hydraulically-driven 30 mm rotary cannon with a high rate of fire of about 4,200 rounds per minute. Without precision components, the cannon can easily jam during operation. The high rate of fire causes significant wear on the cannon’s breech bolt.

As a result, the bolt has a short operating life and must be easily replaceable. Brinkman Defense was tasked with manufacturing replacement bolts for the A-10 Warthog’s 30 mm cannons. Challenges of this ongoing project include:

  • Extreme manufacturing precision to ensure tolerance limits are strictly observed and maintained to prevent the bolt from causing the cannon to jam while firing
  • Prohibitively expensive, difficult-to-machine bolt material, which creates incredibly costly manufacturing errors

To meet the quality requirements and ensure low defect rates, we only manufacture 100 bolts per run. Each part goes through a full quality control inspection. Rather than spot-checking, we inspect each individual unit as it comes out of the machine to verify tolerance requirements, proper finishing, and overall part quality. An inspector from the Department of Defense also performs random samplings and verifies that the bolts are manufactured correctly and according to the proper specifications.

The fabrication of breech bolts for the A-10’s cannons relies largely on our turning and milling capabilities. Additionally, we send each part out for a few operations, including the fabrication of the center hole for the firing pin. Each part comes back to us for additional quality inspections between every operation.

We carefully monitor all subcontractor activity well beyond the level at which most companies monitor their contractors. We painstakingly vet and track the performance of each contractor we use, and each has proven their worth many times over.


Quality Standards at Brinkman Defense

At Brinkman Defense, we understand the importance of quality control and assurance for parts used in critical applications. All our components pass stringent internal quality checks and relevant DOD spot checks. Most importantly, however, we can say with confidence that the parts we manufacture perform effectively in the field where it matters most.

Please contact us to learn more about our capabilities with breech bolts or other critical defense components.