Failure to Eject

Failure to eject (FTE) occurs when a spent casing fails to clear the ejection port after firing, often resulting in a “stovepipe” malfunction where the empty brass becomes trapped vertically between the bolt carrier and ejection port. This Type 2 malfunction prevents the next round from chambering and stops your AR-15 from cycling properly.

Why FTE Matters for AR-15 Builders

Understanding failure to eject is important because it directly relates to several components you’ll select when using the AR15 Outfitters builder. Your choice of bolt carrier group, recoil spring weight, and gas system length all influence ejection reliability. A properly configured AR-15 should eject spent casings at the 3-4 o’clock position; consistent stovepipe malfunctions indicate a build issue that needs addressing.

Common Causes and Build Considerations

FTE typically stems from three main areas:

• Extractor issues: Weak extractor spring tension (below 5 lbs) or worn extractor claws fail to maintain grip on the casing rim during extraction
• Ejector problems: Insufficient ejector spring pressure or a broken ejector prevents the casing from being kicked clear of the ejection port
• Gas system timing: Undergassed rifles (common with carbine-length systems on 16″ barrels) don’t generate enough bolt velocity for reliable ejection

Practical Prevention Tips

When building your AR-15, match your recoil spring weight to your gas system: typically 5.0-5.4 oz buffer for carbine systems, 3.8-4.6 oz for mid-length. Quality ammo matters too; steel-cased ammunition generates less chamber pressure and increases FTE risk by approximately 15% compared to brass. During assembly, ensure your ejector moves freely and produces 4-6 lbs of spring pressure when compressed. Regular maintenance of these components, particularly after 5,000 rounds, helps prevent failure to eject issues before they start.