Technical Bulletin

September 13, 1999

Technical Bulletin 5: Inspection of AR-10 Extractors

Recent Internet and repair calls led to the discovery that a small number of AR-10B series extractors provide marginal extraction. The problem is especially vexing if combined with roughness or dust in the chamber (see Technical Bulletin 1, Failures to Extract from Chrome-Lined Barrels).

All AR-10s are test fired before shipping, so few rifles demonstrate the problem in the field. This Technical Bulletin is intended to provide information useful in identifying the problem extractors for exchange.

The problem may be present if extraction is incomplete or the cartridge is not ejected. The first step in analyzing the problem is to test fire the rifle with high quality, factory fresh ammunition. Dirty, damaged, or reloaded ammunition may provide an incorrect picture of rifle function. If the ammunition is good and extraction is definitely a problem, then additional steps should be taken.

The second step is to test the extractor. Hook an empty cartridge under the extractor claw and use it to push the ejector all the way into the bolt face. If the extractor claw won't catch and hold the cartridge, the extractor hook is too short, the extractor groove is too narrow, or the pinhole in the bolt or extractor is in the wrong position.

If the rim of the cartridge does fit under the extractor, it's possible that a portion of the extractor is still short or a burr is present on the bolt face. In either case the cartridge base may be catching slightly on the intersection, or corner, of the bolt face and the extractor channel. To check for this condition, repeat the test above, but then release pressure on the cartridge and allow the ejector spring to slowly push the cartridge in the direction of the extractor as if it were being ejected. It should pivot out from under the extractor smoothly. An interference problem is detected by a "catch" before the cartridge breaks free. In an extreme case the cartridge may actually be caught in a "half-ejected" position on the bolt face.

If the bolt assembly fails either test it should be returned to ArmaLite for inspection and correction. Call for a return authorization. The rifle or upper receiver assembly should not be returned. Defective components still under warranty will be inspected and corrected at no charge.

MAW

© 1999 ArmaLite, Inc.