Tech Note

TECHNICAL NOTE 31,
Improved AR-10B Rifle Parts

BACKGROUND: Since the introduction of the AR-10B series of rifles, ArmaLite has made improvements to several small parts that have improved safety, reliability, or convenience. This Technical Note is intended to advise ArmaLite's customers of the changes so that they can update their rifles to the latest configuration.

FIRING PIN SPRING: The firing pin spring reduces the firing pin mark made on the primer as the rifle bolt closes, and prevents the possibility of slamfire. This mark is a characteristic of all Ml, M14/MlA, and M16 type Rifles. The latest generation of firing pin spring has a tight end of the firing pin spring is slipped over the front of the firing pin first. It engages a groove on the firing pin, which prevents loss of the spring. THE FIRING PIN SPRING IS AN IMPORTANT SAFETY DEVICE AND MUST NOT BE REMOVED OR LOST. If lost or damaged (or of the older style without the tight end) it will be replaced by ArmaLite at no charge.

FIRING PIN RETAINER: The first firing pin retainers were machined. Later retainers are similar to those of the M-16, but are somewhat longer. These parts are provided in Field Repair Kits or sold as replacement parts.

EXTRACTOR SPRING PLUG: This is an elastomer plug that reinforces the extractor spring and extends its life. The first rifles had no plug. Later rifles included a black or brown plug. The latest plug is more precisely made, and is white or translucent. It will be provided to AR-10 owners at no charge.

EXTRACTOR SPRING REINFORCEMENT RING: This ring was developed by the Naval Surface Warfare Center at Crane, Indiana, for use with the M4 carbine. It was added to the AR-10 in the Summer of 2000. It provides additional reinforcement to the heavily-stressed extractor spring.

Firing pin retaining pins are cataloged parts.

Firing Pin Springs, Extractor Spring Plugs, and Extractor Spring Reinforcement Rings are provided at no charge to rifle owners who need them for their rifles. Customers may request these no-charge parts by mail or email only, providing the serial number of their rifle(s) and a good mailing address.

Copyright © 1999 ArmaLite, Inc.