P320 Testing - Tolerance Stacking & The Thousand Slices of Swiss Cheese

We examined the claim that the conditions required to create a mechanical situation in which a pistol could fire without a trigger pull are so complex that they cannot be intentionally reproduced. Some suggest this explains why no one has ever demonstrated a repeatable, real-world scenario in which a P320 fires without the trigger being pulled.

To put that theory to the test, we took one of our dedicated test pistols and intentionally introduced a wide range of severe mechanical issues, including:

- Bent springs
- Bent striker lock
- Loose striker housing
- Loose striker diameter and foot fit
- Chiseled striker foot
- Crushed reset spring
- Extremely loose slide-to-FCU fit
- Roughened surface finishes on parts
- No striker lock spring
- Offset housing pin
- Worn sear
- Crossed sear springs
- Dead sear springs
- Inverted striker lock spring
- Bent takedown safety lever interference
- Grit and fouling in the fire control unit
- Loose sear housing
- Undersized pins

With all of these faults intentionally incorporated, the pistol was subjected to repeated drop testing and extreme vibration.
Despite the combination of compromised components and aggressive testing, Grayguns could not produce any mechanical condition that allowed the pistol to fire without a trigger pull. The results consistently showed no unintended firing events under any of the imposed scenarios.