How To Tell If Ammo Is Bad: A Technical Guide To Ammunition Inspection And Safety

Ammunition remains reliable for decades when stored in cool, dry environments, but exposure to moisture, extreme heat, and physical damage can cause propellant degradation, priming compound failure, and dangerous malfunctions. Visual inspection combined with mechanical checks provides the definitive method for identifying compromised cartridges before they are loaded into a firearm.

Pre-Inspection Setup and Environmental Standards

Evaluating ammunition requires a systematic approach to workspace safety, proper illumination, and precision measurement tools. Before sorting through surplus or aging inventory, shooters must establish a static-free, well-lit environment free of open flames, sparks, or electronic heating elements.

• Essential Gear: Calibrated digital caliper, clean lint-free work surface, bright LED inspection light, container for suspect cartridges, and protective safety eyewear.
• Prerequisite Knowledge: Familiarity with standard SAAMI (Sporting Arms and Ammunition Manufacturers' Institute) specifications, propellant volatility characteristics, and primer types (corrosive versus non-corrosive).
• Time & Budget Benchmark: An evaluation of 500 rounds takes approximately 30 to 45 minutes; financial investment is limited to basic measurement tools if not already owned.

Step-by-Step Ammunition Inspection Protocol

Step 1: Conduct a Visual Examination for Corrosion and Verdigris

Examine the exterior surfaces of the brass, steel, or aluminum casing for signs of chemical degradation, pitting, or rust. Green, white, or powdery blue oxidation—commonly known as verdigris—often forms when brass reacts with moisture and chemical residues, such as residual salts from old primers or storage containers.

1. Inspect the entire length of the cartridge body, rotating it under bright LED light to catch micro-fractures and surface discoloration.
2. Differentiate between minor cosmetic tarnish (dull brass or dark spots that are completely smooth) and active pitting or corrosion, which weakens the structural integrity of the metal.
3. Reject any cartridge that displays deep pitting, active rust on steel casings, or heavy white/green buildup around the mouth or primer pocket.

Warning: Never attempt to clean deep corrosion off cartridge cases using abrasive power tools or harsh chemical solvents, as this thins the brass wall and introduces microscopic structural vulnerabilities.

Step 2: Check for Physical Deformation and Structural Compromise

Inspect the geometry of the cartridge to ensure it conforms to factory dimensions and has not been subjected to crushing forces, improper reloading techniques, or severe weapon drops.

1. Measure overall length (OAL) using a digital caliper and compare it against published SAAMI maximum cartridge dimensions for that specific caliber.
2. Look for severe dents in the body, bulges near the web, or crimp failures where the bullet is pushed too deeply into the case (setback) or pulled loosely outward.
3. Roll unseated loose rounds across a flat glass surface to detect rim warp or bent case walls; any wobble indicates a compromised baseline geometry.

Pro-Tip: Bullet setback is particularly dangerous because it drastically reduces internal case capacity, causing catastrophic chamber pressure spikes upon ignition. If a round chambers with an unusually short OAL, discard it immediately.

Step 3: Evaluate Primer Integrity and Seal Quality

The primer is the most sensitive and vulnerable component of a modern cartridge, relying on a delicate primary explosive mixture that degrades rapidly upon direct contact with oils, solvents, or moisture.

1. Inspect the primer pocket for a complete, uniform seal, ensuring the primer is seated flush with or slightly below the base of the case head.
2. Check for primer protrusion (seated too high), which can cause slam-fires in semi-automatic firearms or light primer strikes due to cushioning.
3. Look for staining, dark rings, or fluid seepage around the perimeter of the primer, which indicates that cleaning oils, gunsmithing solvents, or water have migrated past the sealant and deactivated the priming compound.

Step 4: Perform the Sound and Shake Test for Propellant State

When handling older military surplus ammunition or bulk rounds stored in unknown conditions, internal propellant degradation can occur without external symptoms.

1. Hold a single rifle or pistol cartridge between your thumb and index finger close to your ear.
2. Gently shake the cartridge along its longitudinal axis and listen carefully for the distinct shifting sound of dry, granular powder kernels moving freely.
3. If the powder sounds clumped, makes a dull thud, or makes no sound at all, the propellant may have agglomerated due to extreme moisture exposure, altering its burn rate unpredictably.

Ammunition Condition Reference Matrix

Common Ammunition Failures and Field Remedies

Recognizing the symptoms of bad ammunition prevents dangerous malfunctions and helps diagnose improper storage conditions before entire stockpiles are compromised.

• Root Cause (Primer Contamination): Lubricants or cleaning solvents migrated into the primer pocket during weapon maintenance.
  
  
  • Actionable Fix: Discard the affected round. Review cleaning protocols to ensure the firearm chamber and bolt face are completely dry before loading ammunition.
• Root Cause (Neck Splits from Age/Brittle Brass): Repeated expansion and contraction or environmental chemical exposure hardened the brass cartridge neck, making it brittle.
  
  
  • Actionable Fix: Sort through older surplus lots, inspect case mouths with a magnifying glass for radial micro-cracks, and scrap any batches displaying greater than a two percent split rate.
• Root Cause (Hangfire or Squat Load): Degraded smokeless powder burns slowly or fails to build enough pressure to exit the barrel, leaving a projectile lodged in the bore.
  
  
  • Actionable Fix: If a pulled trigger results in a delayed report (hangfire) or an unusually muffled report with low recoil (squat), keep the muzzle pointed downrange for 60 seconds. Clear the firearm and inspect the bore with a cleaning rod to ensure no bullet obstruction remains before firing another round.

Frequently Asked Questions

How long does standard ammunition last in storage?

Factory ammunition stored in cool, dark, and dry conditions (ideally 55 to 65 degrees Fahrenheit with relative humidity below 50 percent) remains fully functional for decades. Many military surplus rifle rounds manufactured in the mid-20th century still fire reliably today because sealed packaging protected the components from atmospheric moisture.

Is green corrosion on brass ammunition dangerous?

Surface tarnish that leaves the brass smooth is generally harmless, but green verdigris or white powdery corrosion indicates active chemical degradation that eats into the metal walls. If the corrosion is deep enough to cause pitting or structural thinning, the case can rupture upon firing, releasing high-pressure gas into the firearm action.

Can I shoot ammunition that has been submerged in water?

If modern waterproof-sealed ammunition was briefly submerged in clean water and dried immediately, it may still fire, but water frequently migrates past primer seals and neck tension barriers. It is safer to discard any ammunition that experienced prolonged immersion, as contaminated powder and deactivated primers create a high risk of squib loads.

What should I do with defective or bad ammunition?

Never throw damaged ammunition into household trash, municipal recycling bins, or outdoor fires. Contact a local commercial shooting range, hazardous waste disposal facility, or law enforcement agency to inquire about safe surrender protocols for unstable or unserviceable ordnance.

Does extreme heat damage modern ammunition?

Prolonged exposure to temperatures exceeding 135 degrees Fahrenheit can break down the chemical stabilizers in smokeless gunpowder, altering its burn rate and generating excessive chamber pressures. Avoid storing ammunition in uninsulated attics, vehicle trunks during summer months, or direct sunlight.

Secure Your Inventory and Ensure Range Safety

Properly evaluating your ammunition stockpile guarantees consistent ballistic performance while protecting both your firearms and personal safety from catastrophic failures. Implement these rigorous inspection standards today to separate serviceable rounds from compromised inventory before your next trip to the range.