Operational history prior to the accident

Operational history before the incident

Factory test firing by the manufacturer:
• Bullet weight: 300 gr.
• Approximately 25 rounds fired.
• Average muzzle velocity spread: 3 m/s.
• Pressure remained within the working range of 420–450 MPa.
• Firing was conducted with prepared zero-cycle brass matching the chamber geometry with a 0.369" neck.
• Powder used – VihtaVuori N570 with charges of 112–115 grn.
• No signs of excessive pressure in the locking assembly or unstable operation were detected.

Barrel break-in by a third-party specialist
• Break-in was performed by a third-party specialist.
• Hand-loaded ammunition was used, assembled by a party other than the rifle manufacturer.
• The exact number of rounds fired has not been reliably established.
• No signs of emergency conditions or failures were recorded.

Incident shooting by the rifle owner
• Firing was performed by the rifle owner.
• Non-factory ammunition was used, assembled by an unknown individual.
• Bullet weight: 300 gr.

First shot:
• Muzzle velocity: 978 m/s.
• The shot was fired in normal mode.

Second shot:
• Muzzle velocity: 860 m/s.
• A catastrophic failure occurred on this shot.

Chronological conclusion
• Factory and third-party tests confirm correct operation of the design when using zero-cycle brass.
• The failure occurred during firing by the owner using ammunition of unknown assembly.
• The sharp drop in velocity indicates an extremely rapid pressure spike.