Unusual Applications: Bullet Shells & Crimping

From time to time, when we receive unique inquiries, we like to think outside of the box and try something different from the traditional cap and bottle testing Mesa is known for. With simple tooling and programming changes, we can often accommodate unusual torque testing requests. For example, recently we discovered how an automatic torque tester can help in the quality control of crimped bullets/shells.

According to americanrifleman.org, crimping bullets properly is a constant problem. Crimping too heavily could push MAPs over the limit, which affects accuracy and causes leading. Crimping too lightly can “result in erratic breech pressures, high variations in muzzle velocity, excess unburned propellant and malfunctions in semi-automatic firearms.”

This issue is well known among gun owners. According to various forums, certain ammo brands are often associated with poor quality crimps and noticeable variation in accuracy/velocity. When terms such as “loose in the case” or “problematic” are often mentioned in relation to a specific ammo brand, it is clear that they may have quality control issues. It is time to pay attention to the “crimp torque”!

Quality control of crimped bullets is possible by using a slightly modified SureTorque tester. After making the appropriate changes to parts, and programming the machine to rotate the bullet in the case 360 degrees, the machine can automatically measure the peak and average “crimp torque”. The peak value and the angle-torque profile can be used to identify issues with the crimping equipment.

Once the process limits are established, it is easy to monitor the crimping process by running a torque test on bullets every half hour or so. Measurement results out of the acceptable process range can trigger an audio/visual alarm notifying the crimping machine operator that a tooling is worn or an adjustment is due.

The video below shows how our Mesa Torque Testers, with some re-design, can fit this application.