Forensic engineering expert witness for defense advises on firearm that ‘exploded’ in shooter’s face

The plaintiff was injured when a 50-caliber muzzle-loader rifle manufactured by the defendant exploded in his face. The gun was previously owned when the plaintiff received it as a gift from his father. The gun was not corroded and was in sufficiently good shape for him to believe it was safe to shoot. He was not aware of any modifications made by the prior owners, and no one in his family replaced any parts on the muzzle loader. The gun was professionally cleaned one time, and the plaintiff had personally cleaned it 10 or 15 times. Prior to the accident, the plaintiff had fired the gun 40 to 50 times. Following the accident, the plaintiff’s brother collected all parts of the exploded gun that he could find. Some parts are missing.

The plaintiff asserted claims for manufacturing and design defect under the state Products Liability Act and sought to recover for his injuries.

Question(s) For Expert Witness

1. Were there any defects in the gun?

2. Why did it fail?

Expert Witness Response

I examined and tested the subject firearm and its component parts and reviewed documents, following the protocols and procedures generally accepted and commonly used by experts in failure analysis and the engineering analysis of accident causation. Particular attention was directed to the threaded connections that joined the breech plug to the barrel and the end cap to the rear of the receiver. The receiver end cap, striker spring, striker handle retainer, striker handle, breech plug, and nipple of the subject firearm have never been presented for examination. These parts are presumably the parts that plaintiff alleges were expelled from his firearm. No recovered pieces of the subject muzzle loader exhibited damage or caused the incident in question. Based on plaintiff’s description o the incident, the breech plug was expelled from the rifle upon the last firing. The breech plug closes the rear of the barrel and is subjected to the pressures involved in the firing. Firing the subject rifle over the period of two years preceding the incident did not cause expulsion of the breech plug, bolt and receiver end cap. Had there been a defect in the threaded connection between the barrel and the factory-supplied breech plug, such defect would have evidenced itself during the period of use prior to the incident. Firing a rifle using a proper loading of propellant powder and a proper projectile will not cause expulsion of a properly threaded and properly installed breech plug. The breech plug was not properly installed in the rear of the barrel prior to the last firing. There were no defects in the barrel and receiver of the rifle that either caused or contributed to the accident. There was no defect in the threaded connection between the subject rifle barrel and the factory-supplied breech plug at the time the subject rifle left the hands of the manufacturer. There were no defects in design, materials or manufacture of the subject rifle. Failure was caused by gross misuse of the rifle that could not have been foreseen or guarded against by the manufacturer.

The expert is a registered professional engineer who specializes in and teaches metallurgical engineering. He has more than 45 years of experience in consulting for companies that manufacture and distribute firearms and ammunition.