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Smart Gun Sizing

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Smart Gun Sizing

Grip sizing ensures that The Biofire Smart Gun provides reliable biometric authentication by positioning the fingerprint sensor where the pad of your middle finger naturally rests. Precise sizing is important for the Smart Gun to authenticate authorized users consistently and quickly.

Sizing for Biometric Performance

The Smart Gun uses the Guardian Biometric Engine with integrated biometric sensors to authenticate users, which enables firing by authorized users, unlike traditional firearms that rely only on mechanical safeties. Fingerprint identification occurs through a fingerprint sensor that sits where the user's middle finger of their dominant hand naturally rests when gripping the firearm.

Position the pad of your middle finger flush, and naturally, on the sensor surface to support reliable biometric authentication. If the pad of your finger does not make proper contact with the sensor, the grip could be too large or too small. Improper contact could reduce performance or inhibit authentication of an authorized user using the fingerprint sensor.

Human hands vary significantly in size and shape, and what feels natural and comfortable for one shooter may be awkward or uncomfortable for another. Biofire's grip sizing process is intended to configure the Smart Gun to best fit the primary user's hand, and included backstraps allow for additional adjustment.

Importance of Proper Grip and Fit:

  • Establish reliable fingerprint sensor contact
  • Improve comfort and control when handling the firearm
  • Support consistent performance during use

Whether you are new to firearms or just new to the Smart Gun, please take the time to complete grip sizing correctly to ensure your Smart Gun is manufactured with the optimal fit for you.

Size Determination

Biofire will send you a Grip Sizing Template after you finalize your order. This template is specially designed to gather precise measurements of the primary user's hand. Using calibration markers on the template, Biofire reviews a photograph of the user's hand to determine the appropriate grip configuration. Your Smart Gun will come configured with the grip size and sensor placement that matches the primary user's measurements. Interchangeable backstraps are included that allow you to fine-tune the fit for maximum comfort, or adjust for additional users.

Please follow all instructions and tips that accompany your Grip Sizing Template to ensure your Smart Gun can be properly configured for your hand size.

Please refer to the Grip Sizing Template article for more information.

All personal information collected is subject to Biofire's Privacy Policy available at smartgun.com/legal/privacy-policy

Multiple Users, Multiple Sizes

Biofire recommends sizing the grip for the primary user of your Smart Gun. If you plan to an additional "primary user", you may submit an additional Grip Sizing image with their hand, and Biofire will recommend a size that will work best for both users if that user has the same dominant hand. Keep in mind that the recommended grip size may be a compromise between both users' ideal fit, and that utilizing facial recognition may be a better solution in some scenarios. Modifying the Smart Gun grip using the included backstraps can provide some adjustability for secondary users with different hand sizes as well.

Last updated on June 9, 2026

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© 2026 Biofire. All rights reserved. Smart Gun, Biofire, the Biofire wordmark, and the Biofire logo are trademarks of Biofire in the United States and/or other countries. All images and renders on this page represent pre-production models and final Biofire products may differ from the images shown. All claims are subject to change and qualification. Final product specifications will be provided at or prior to final purchase. Privacy Policy

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