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Manufacturing
11 min read
Areas of Expertise :
Ballistics And Firearms, Human Factors, Product Defect, Product Liability, Accident Investigation
Published Date:
Last Modified Date:
Jurisdiction:
Federal. Second Circuit
Colwell v. Sig Sauer, Inc. is a federal diversity product-liability action applying New York law. The lawsuit arose after Michael Colwell, a Troy Police Department sergeant, alleged that his department-issued Sig Sauer P320 pistol discharged during a police training exercise in New York. Colwell claimed that the pistol fired while it was holstered on his right hip, causing a serious injury to his right leg. His wife, Julia Colwell, also asserted a loss of consortium claim.
The lawsuit focused on whether the P320 was defectively designed because it lacked external safety features, including a manual thumb safety or a tabbed trigger safety. The complaint alleged that the pistol fired without a trigger pull. On appeal, however, the Second Circuit described the record more narrowly. The court stated that the Colwells and their experts did not argue that the pistol fired spontaneously, and there was no dispute that the P320 cannot discharge unless its trigger is depressed. Their remaining theory was that an unknown object or contact within or near the holster may have actuated the trigger while the pistol was holstered.
The case also addressed the role of expert testimony under Federal Rule of Evidence 702. The district court excluded the plaintiffs’ expert causation opinions and granted summary judgment for Sig Sauer on the strict products liability and negligence claims. The Second Circuit affirmed the exclusion of those causation opinions, but vacated the summary judgment ruling and remanded the case. The appellate court did not decide liability. It held only that the remaining record could allow a jury to consider causation without the excluded expert causation opinions.
Michael Colwell was participating in a firearms training exercise in New York with his department-issued Sig Sauer P320 and live ammunition. According to the complaint and Colwell’s testimony, he had placed the pistol in a holster on his right hip and was reaching across his body to draw a simulated taser when the pistol discharged. The complaint alleged that the bullet struck his upper right thigh, traveled through his quadriceps muscle, and exited above his right knee.
Court records also noted conflicting accounts of the incident. Colwell testified that the pistol was holstered when it fired. Other reports described him as manipulating the firearm or attempting to holster the pistol when the discharge occurred. Those factual disputes became part of the causation record, along with the P320’s trigger system, the holster evidence, and the plaintiffs’ theory that external safety features could have reduced the risk of unintended trigger actuation.
Michael and Julia Colwell filed suit against Sig Sauer in the U.S. District Court for the Northern District of New York. Michael Colwell asserted New York law claims for strict products liability, negligence, breach of implied warranty of merchantability, breach of express warranty, negligent infliction of emotional distress, and intentional infliction of emotional distress. Julia Colwell asserted a loss of consortium claim.
The plaintiffs alleged that the P320 was defectively designed because its trigger system, internal safety features, and lack of external safeties created an unintended-discharge risk. Their design-defect theory focused on external safety features, including a manual thumb safety or a tabbed trigger safety. Sig Sauer denied that the P320 was defective and disputed the plaintiffs’ causation theory.
Chief Judge Brenda K. Sannes ruled on Sig Sauer’s motions to exclude certain expert testimony and its motion for summary judgment. The plaintiffs offered opinions from James Tertin, a gunsmith and firearms expert, and Dr. William J. Vigilante, Jr., a human factors engineer.
Tertin inspected and analyzed the P320 used by Colwell and addressed the pistol’s trigger system, internal safeties, lack of external safeties, and possible alternative designs. Vigilante addressed the P320 from a human factors viewpoint, including user interaction with the pistol and the possible role of a tabbed trigger safety.
The district court excluded both experts’ specific causation opinions under Federal Rule of Evidence 702. The court found that those opinions did not reliably explain how the alleged design defect caused Colwell’s specific accident. The exclusion applied to the challenged causation opinions, not to every design-defect opinion about the P320’s trigger system or proposed external-safety alternatives. After excluding the causation opinions, the court granted summary judgment to Sig Sauer on the strict products liability and negligence claims.
After the district court entered summary judgment on the strict products liability and negligence claims, the parties addressed the claims that had not been resolved by that order. The Second Circuit later noted that the parties stipulated to dismissal of the remaining claims, which allowed appellate review to proceed.
The appeal addressed two central questions. First, the Second Circuit considered whether the district court properly excluded the expert causation opinions. Second, it considered whether New York product-liability law required expert causation testimony on the record before the court. The strict products liability and negligence claims reached the Second Circuit after judgment had been entered for Sig Sauer.
The U.S. Court of Appeals for the Second Circuit heard oral argument in the consolidated appeal. The panel reviewed the district court’s Rule 702 ruling and its conclusion that proximate causation could not go to a jury without admissible expert causation testimony.
The appellate record included the opinions offered by Tertin and Vigilante for the Colwells, along with Sig Sauer’s opposing expert evidence. The record also included the P320 design-defect theory, Colwell’s account of the incident, conflicting reports about the discharge, the holster evidence, and the disputed role of external safety features.
The Second Circuit affirmed the exclusion of the causation opinions offered by Tertin and Vigilante. The court found that those opinions lacked a reliable foundation because they did not adequately address the circumstances of Colwell’s accident.
The appellate opinion also identified Derek Watkins as Sig Sauer’s expert. Watkins contended that the P320 was sufficiently safe without external safeties and that Colwell’s accident was caused by his handling of the pistol. His opinions supported Sig Sauer’s defense against the plaintiffs’ design-defect and causation allegations.
The Second Circuit then held that the district court applied too broad a causation rule by treating expert causation testimony as necessary on this record. The court concluded that jurors could consider the remaining design-defect evidence, Colwell’s account, and the physical evidence involving the P320 and holster. The remand analysis rested most directly on the tabbed-trigger theory, not the manual thumb-safety theory.
The court addressed the manual thumb-safety theory separately. It stated that the Colwells had not raised a material fact issue on whether a manual thumb safety would have prevented the accident because there was no evidence that Colwell would have engaged it.
The Second Circuit also declined to affirm summary judgment under New York’s optional-equipment doctrine. The court found that Sig Sauer had not shown, on the summary-judgment record, that the Troy Police Department was actually aware of the manual-safety option or that normal circumstances of P320 use did not involve the alleged defect.
The panel’s decision was divided. Judge Richard J. Sullivan dissented from the majority’s decision to vacate summary judgment. The Second Circuit vacated the judgment and remanded the case for further proceedings. The ruling allowed the strict products liability and negligence claims to continue based on the remaining evidence, but it did not decide whether Sig Sauer was liable.
Court:
United States Court of Appeals for the Second Circuit
Case Name:
Colwell v. Sig Sauer, Inc.
Causation Analysis
Design Defect
Firearms
Product analysis
Product Safety
Safety
Safety Engineering
Colwell v. Sig Sauer, Inc. is a federal diversity product-liability action applying New York law. The lawsuit arose after Michael Colwell, a Troy Police Department sergeant, alleged that his department-issued Sig Sauer P320 pistol discharged during a police training exercise in New York. Colwell claimed that the pistol fired while it was holstered on his right hip, causing a serious injury to his right leg. His wife, Julia Colwell, also asserted a loss of consortium claim.
The lawsuit focused on whether the P320 was defectively designed because it lacked external safety features, including a manual thumb safety or a tabbed trigger safety. The complaint alleged that the pistol fired without a trigger pull. On appeal, however, the Second Circuit described the record more narrowly. The court stated that the Colwells and their experts did not argue that the pistol fired spontaneously, and there was no dispute that the P320 cannot discharge unless its trigger is depressed. Their remaining theory was that an unknown object or contact within or near the holster may have actuated the trigger while the pistol was holstered.
The case also addressed the role of expert testimony under Federal Rule of Evidence 702. The district court excluded the plaintiffs’ expert causation opinions and granted summary judgment for Sig Sauer on the strict products liability and negligence claims. The Second Circuit affirmed the exclusion of those causation opinions, but vacated the summary judgment ruling and remanded the case. The appellate court did not decide liability. It held only that the remaining record could allow a jury to consider causation without the excluded expert causation opinions.
Michael Colwell was participating in a firearms training exercise in New York with his department-issued Sig Sauer P320 and live ammunition. According to the complaint and Colwell’s testimony, he had placed the pistol in a holster on his right hip and was reaching across his body to draw a simulated taser when the pistol discharged. The complaint alleged that the bullet struck his upper right thigh, traveled through his quadriceps muscle, and exited above his right knee.
Court records also noted conflicting accounts of the incident. Colwell testified that the pistol was holstered when it fired. Other reports described him as manipulating the firearm or attempting to holster the pistol when the discharge occurred. Those factual disputes became part of the causation record, along with the P320’s trigger system, the holster evidence, and the plaintiffs’ theory that external safety features could have reduced the risk of unintended trigger actuation.
Michael and Julia Colwell filed suit against Sig Sauer in the U.S. District Court for the Northern District of New York. Michael Colwell asserted New York law claims for strict products liability, negligence, breach of implied warranty of merchantability, breach of express warranty, negligent infliction of emotional distress, and intentional infliction of emotional distress. Julia Colwell asserted a loss of consortium claim.
The plaintiffs alleged that the P320 was defectively designed because its trigger system, internal safety features, and lack of external safeties created an unintended-discharge risk. Their design-defect theory focused on external safety features, including a manual thumb safety or a tabbed trigger safety. Sig Sauer denied that the P320 was defective and disputed the plaintiffs’ causation theory.
Chief Judge Brenda K. Sannes ruled on Sig Sauer’s motions to exclude certain expert testimony and its motion for summary judgment. The plaintiffs offered opinions from James Tertin, a gunsmith and firearms expert, and Dr. William J. Vigilante, Jr., a human factors engineer.
Tertin inspected and analyzed the P320 used by Colwell and addressed the pistol’s trigger system, internal safeties, lack of external safeties, and possible alternative designs. Vigilante addressed the P320 from a human factors viewpoint, including user interaction with the pistol and the possible role of a tabbed trigger safety.
The district court excluded both experts’ specific causation opinions under Federal Rule of Evidence 702. The court found that those opinions did not reliably explain how the alleged design defect caused Colwell’s specific accident. The exclusion applied to the challenged causation opinions, not to every design-defect opinion about the P320’s trigger system or proposed external-safety alternatives. After excluding the causation opinions, the court granted summary judgment to Sig Sauer on the strict products liability and negligence claims.
After the district court entered summary judgment on the strict products liability and negligence claims, the parties addressed the claims that had not been resolved by that order. The Second Circuit later noted that the parties stipulated to dismissal of the remaining claims, which allowed appellate review to proceed.
The appeal addressed two central questions. First, the Second Circuit considered whether the district court properly excluded the expert causation opinions. Second, it considered whether New York product-liability law required expert causation testimony on the record before the court. The strict products liability and negligence claims reached the Second Circuit after judgment had been entered for Sig Sauer.
The U.S. Court of Appeals for the Second Circuit heard oral argument in the consolidated appeal. The panel reviewed the district court’s Rule 702 ruling and its conclusion that proximate causation could not go to a jury without admissible expert causation testimony.
The appellate record included the opinions offered by Tertin and Vigilante for the Colwells, along with Sig Sauer’s opposing expert evidence. The record also included the P320 design-defect theory, Colwell’s account of the incident, conflicting reports about the discharge, the holster evidence, and the disputed role of external safety features.
The Second Circuit affirmed the exclusion of the causation opinions offered by Tertin and Vigilante. The court found that those opinions lacked a reliable foundation because they did not adequately address the circumstances of Colwell’s accident.
The appellate opinion also identified Derek Watkins as Sig Sauer’s expert. Watkins contended that the P320 was sufficiently safe without external safeties and that Colwell’s accident was caused by his handling of the pistol. His opinions supported Sig Sauer’s defense against the plaintiffs’ design-defect and causation allegations.
The Second Circuit then held that the district court applied too broad a causation rule by treating expert causation testimony as necessary on this record. The court concluded that jurors could consider the remaining design-defect evidence, Colwell’s account, and the physical evidence involving the P320 and holster. The remand analysis rested most directly on the tabbed-trigger theory, not the manual thumb-safety theory.
The court addressed the manual thumb-safety theory separately. It stated that the Colwells had not raised a material fact issue on whether a manual thumb safety would have prevented the accident because there was no evidence that Colwell would have engaged it.
The Second Circuit also declined to affirm summary judgment under New York’s optional-equipment doctrine. The court found that Sig Sauer had not shown, on the summary-judgment record, that the Troy Police Department was actually aware of the manual-safety option or that normal circumstances of P320 use did not involve the alleged defect.
The panel’s decision was divided. Judge Richard J. Sullivan dissented from the majority’s decision to vacate summary judgment. The Second Circuit vacated the judgment and remanded the case for further proceedings. The ruling allowed the strict products liability and negligence claims to continue based on the remaining evidence, but it did not decide whether Sig Sauer was liable.
1. James Tertin: Plaintiffs’ Gunsmith and Firearms Expert Witness
James Tertin was offered by the Colwells as a gunsmith and firearms expert. His opinions addressed the P320’s trigger system, short trigger travel, internal safety mechanisms, lack of external safeties, and possible alternative external safety features such as a manual thumb safety or tabbed trigger safety. He also inspected and analyzed the P320 used by Colwell.
The district court excluded his specific causation opinions after finding that they did not reliably explain how the alleged defect caused the discharge in Colwell’s incident. The Second Circuit affirmed that exclusion, finding that the causation opinion did not adequately account for the facts of the accident.
2. Dr. William J. Vigilante, Jr.: Plaintiffs’ Human Factors Expert Witness
Dr. William J. Vigilante, Jr. was offered by the Colwells as a human factors engineer. His opinions addressed the P320’s lack of external safety features, user interaction with the pistol, and whether a tabbed trigger safety could have reduced the risk of unintended discharge. His work supported the plaintiffs’ design-defect theory.
The district court excluded his specific causation opinions after finding that they did not reliably connect the alleged design issues to the discharge that injured Colwell. The Second Circuit affirmed that part of the ruling, while allowing the case to proceed on the remaining record.
3. Derek Watkins: Sig Sauer Expert Witness on P320 Safety and Handling
Derek Watkins was identified as Sig Sauer’s expert. The appellate opinion described his opinions on P320 safety, external safeties, and firearm handling. Watkins contended that the P320 was sufficiently safe without external safeties and that Colwell’s accident was caused by Colwell’s handling of the pistol. His opinions supported Sig Sauer’s defense against the design-defect and causation allegations.
1. Complaint Allegations Compared With the Appellate Record
The complaint alleged that the P320 fired without a trigger pull and described the pistol as capable of firing by itself. The Second Circuit’s analysis used a narrower appellate record. The court stated that the Colwells and their experts did not claim spontaneous firing on appeal and that there was no dispute that the P320 cannot discharge unless the trigger is depressed.
2. Federal Rule of Evidence 702 and the Expert Causation Decision
Federal Rule of Evidence 702 governed whether the challenged expert causation opinions could be admitted. The district court excluded the plaintiffs’ causation opinions because the experts did not reliably explain how the alleged defect caused this specific discharge. The Second Circuit affirmed that part of the ruling.
3. P320 Design-Defect Evidence and Specific Causation
The appellate decision separated general design-defect evidence from opinions about what caused Colwell’s particular accident. The Second Circuit agreed that the expert causation opinions were properly excluded, but it did not treat that exclusion as the end of the case. The court held that the remaining evidence could still allow a jury to evaluate causation.
4. Tabbed Trigger Theory Compared With Manual Thumb Safety Theory
The Second Circuit treated the two proposed external-safety theories differently. The court found that the tabbed-trigger theory could proceed because a jury could consider whether a tabbed trigger safety would have reduced the risk of unintended trigger actuation. By contrast, the court found that the manual thumb-safety theory did not raise a material fact issue because the record did not show that Colwell would have engaged a manual safety.
5. New York Product Liability Causation and Optional Equipment
The district court concluded that expert causation testimony was required because the mechanics of the firearm were outside ordinary juror knowledge. The Second Circuit rejected that broad application of New York causation law on this record. It held that jurors may rely on physical evidence, witness testimony, and common reasoning in some design-defect cases, depending on the proof.
Sig Sauer also argued that summary judgment could be affirmed under New York’s optional-equipment doctrine. The Second Circuit declined to do so. The court found that Sig Sauer had not shown that the Troy Police Department was actually aware of the manual-safety option or that normal circumstances of P320 use did not involve the alleged defect.
Colwell v. Sig Sauer moved from an alleged police training injury to a federal product-liability dispute over the P320’s design and the evidence needed to connect that design to a specific discharge. The district court excluded the plaintiffs’ expert causation opinions and entered summary judgment for Sig Sauer on the strict products liability and negligence claims.
The Second Circuit changed the case posture in May 2026. It agreed that the expert causation opinions were properly excluded, but ruled in a divided decision that the remaining evidence could still allow a jury to consider the strict products liability and negligence claims. The remand rests most directly on the tabbed-trigger theory. The court did not decide whether Sig Sauer is liable, and the case returned to the district court for further proceedings.
What happened during the Sig Sauer P320 training incident in Colwell v. Sig Sauer?
Michael Colwell alleged that his department-issued Sig Sauer P320 discharged during a June 2, 2021 police training exercise in New York. He claimed the pistol fired while it was in a holster on his right hip and while he was reaching across his body to draw a simulated taser. Court records also noted conflicting accounts about whether he was manipulating or attempting to holster the pistol when it fired.
What design defect did the Colwells allege in the Sig Sauer P320?
The Colwells alleged that the P320 was defectively designed because it lacked external safety features, including a manual thumb safety or tabbed trigger safety. They claimed that an external safety could have reduced the risk of unintended trigger actuation. Sig Sauer denied that the P320 was defective.
Did the Colwells claim the P320 fired spontaneously?
The filed complaint alleged that the pistol fired without a trigger pull, but the Second Circuit described the appellate record differently. The court stated that the Colwells and their experts did not argue that the pistol fired spontaneously. It also noted that there was no dispute on appeal that the P320 cannot discharge unless the trigger is depressed.
Why were the plaintiffs’ expert causation opinions excluded?
The district court found that the plaintiffs’ experts did not reliably explain how the alleged design defect caused this specific discharge. The court focused on the gap between general design opinions and the facts of Colwell’s accident. The Second Circuit later affirmed the exclusion of those causation opinions.
What did the Second Circuit decide in the 2026 Colwell v. Sig Sauer appeal?
The Second Circuit held that the district court properly excluded the plaintiffs’ expert causation opinions. It also held that summary judgment for Sig Sauer was improper on the remaining record. The court vacated the judgment and remanded the case for further proceedings without deciding whether Sig Sauer was liable.
1. James Tertin: Plaintiffs’ Gunsmith and Firearms Expert Witness
James Tertin was offered by the Colwells as a gunsmith and firearms expert. His opinions addressed the P320’s trigger system, short trigger travel, internal safety mechanisms, lack of external safeties, and possible alternative external safety features such as a manual thumb safety or tabbed trigger safety. He also inspected and analyzed the P320 used by Colwell.
The district court excluded his specific causation opinions after finding that they did not reliably explain how the alleged defect caused the discharge in Colwell’s incident. The Second Circuit affirmed that exclusion, finding that the causation opinion did not adequately account for the facts of the accident.
2. Dr. William J. Vigilante, Jr.: Plaintiffs’ Human Factors Expert Witness
Dr. William J. Vigilante, Jr. was offered by the Colwells as a human factors engineer. His opinions addressed the P320’s lack of external safety features, user interaction with the pistol, and whether a tabbed trigger safety could have reduced the risk of unintended discharge. His work supported the plaintiffs’ design-defect theory.
The district court excluded his specific causation opinions after finding that they did not reliably connect the alleged design issues to the discharge that injured Colwell. The Second Circuit affirmed that part of the ruling, while allowing the case to proceed on the remaining record.
3. Derek Watkins: Sig Sauer Expert Witness on P320 Safety and Handling
Derek Watkins was identified as Sig Sauer’s expert. The appellate opinion described his opinions on P320 safety, external safeties, and firearm handling. Watkins contended that the P320 was sufficiently safe without external safeties and that Colwell’s accident was caused by Colwell’s handling of the pistol. His opinions supported Sig Sauer’s defense against the design-defect and causation allegations.
1. Complaint Allegations Compared With the Appellate Record
The complaint alleged that the P320 fired without a trigger pull and described the pistol as capable of firing by itself. The Second Circuit’s analysis used a narrower appellate record. The court stated that the Colwells and their experts did not claim spontaneous firing on appeal and that there was no dispute that the P320 cannot discharge unless the trigger is depressed.
2. Federal Rule of Evidence 702 and the Expert Causation Decision
Federal Rule of Evidence 702 governed whether the challenged expert causation opinions could be admitted. The district court excluded the plaintiffs’ causation opinions because the experts did not reliably explain how the alleged defect caused this specific discharge. The Second Circuit affirmed that part of the ruling.
3. P320 Design-Defect Evidence and Specific Causation
The appellate decision separated general design-defect evidence from opinions about what caused Colwell’s particular accident. The Second Circuit agreed that the expert causation opinions were properly excluded, but it did not treat that exclusion as the end of the case. The court held that the remaining evidence could still allow a jury to evaluate causation.
4. Tabbed Trigger Theory Compared With Manual Thumb Safety Theory
The Second Circuit treated the two proposed external-safety theories differently. The court found that the tabbed-trigger theory could proceed because a jury could consider whether a tabbed trigger safety would have reduced the risk of unintended trigger actuation. By contrast, the court found that the manual thumb-safety theory did not raise a material fact issue because the record did not show that Colwell would have engaged a manual safety.
5. New York Product Liability Causation and Optional Equipment
The district court concluded that expert causation testimony was required because the mechanics of the firearm were outside ordinary juror knowledge. The Second Circuit rejected that broad application of New York causation law on this record. It held that jurors may rely on physical evidence, witness testimony, and common reasoning in some design-defect cases, depending on the proof.
Sig Sauer also argued that summary judgment could be affirmed under New York’s optional-equipment doctrine. The Second Circuit declined to do so. The court found that Sig Sauer had not shown that the Troy Police Department was actually aware of the manual-safety option or that normal circumstances of P320 use did not involve the alleged defect.
Colwell v. Sig Sauer moved from an alleged police training injury to a federal product-liability dispute over the P320’s design and the evidence needed to connect that design to a specific discharge. The district court excluded the plaintiffs’ expert causation opinions and entered summary judgment for Sig Sauer on the strict products liability and negligence claims.
The Second Circuit changed the case posture in May 2026. It agreed that the expert causation opinions were properly excluded, but ruled in a divided decision that the remaining evidence could still allow a jury to consider the strict products liability and negligence claims. The remand rests most directly on the tabbed-trigger theory. The court did not decide whether Sig Sauer is liable, and the case returned to the district court for further proceedings.
What happened during the Sig Sauer P320 training incident in Colwell v. Sig Sauer?
Michael Colwell alleged that his department-issued Sig Sauer P320 discharged during a June 2, 2021 police training exercise in New York. He claimed the pistol fired while it was in a holster on his right hip and while he was reaching across his body to draw a simulated taser. Court records also noted conflicting accounts about whether he was manipulating or attempting to holster the pistol when it fired.
What design defect did the Colwells allege in the Sig Sauer P320?
The Colwells alleged that the P320 was defectively designed because it lacked external safety features, including a manual thumb safety or tabbed trigger safety. They claimed that an external safety could have reduced the risk of unintended trigger actuation. Sig Sauer denied that the P320 was defective.
Did the Colwells claim the P320 fired spontaneously?
The filed complaint alleged that the pistol fired without a trigger pull, but the Second Circuit described the appellate record differently. The court stated that the Colwells and their experts did not argue that the pistol fired spontaneously. It also noted that there was no dispute on appeal that the P320 cannot discharge unless the trigger is depressed.
Why were the plaintiffs’ expert causation opinions excluded?
The district court found that the plaintiffs’ experts did not reliably explain how the alleged design defect caused this specific discharge. The court focused on the gap between general design opinions and the facts of Colwell’s accident. The Second Circuit later affirmed the exclusion of those causation opinions.
What did the Second Circuit decide in the 2026 Colwell v. Sig Sauer appeal?
The Second Circuit held that the district court properly excluded the plaintiffs’ expert causation opinions. It also held that summary judgment for Sig Sauer was improper on the remaining record. The court vacated the judgment and remanded the case for further proceedings without deciding whether Sig Sauer was liable.
Causation Analysis
Design Defect
Firearms
Product analysis
Product Safety
Safety
Safety Engineering
Manufacturing
Metallurgy, +4
Manufacturing
Manufacturing, +4
Manufacturing