Apparatus for measuring the temperature of chambered projectile

A system for measuring the temperature of a chambered projectile in a firearm, the system comprising:

• a stand;
• a firearm supported by the stand, the firearm including a chamber configured to receive an ammunition round, and a barrel including a muzzle and a gas port;
• an inert test ammunition round received within the chamber of the firearm, the test ammunition round including a case, a projectile coupled to the case, and a projectile thermocouple thermally coupled to the projectile and having a wire extending from the projectile through the casing;
• a muzzle thermocouple thermally coupled to the muzzle at the exterior of the barrel of the firearm;
• a gas port thermocouple thermally coupled to the gas port at the exterior of the barrel of the firearm;
• a chamber thermocouple thermally coupled to the chamber at the exterior of the barrel of the firearm;
• a data acquisition system in electrical communication with the projectile thermocouple, the muzzle thermocouple, the gas port thermocouple, and the chamber thermocouple, the data acquisition system receiving signals indicative of temperatures measured by the projectile thermocouple, the muzzle thermocouple, the gas port thermocouple, and the chamber thermocouple;
• and
• a processor in electrical communication with the data acquisition system configured to receive the temperature measurements over time from the projectile thermocouple, the muzzle thermocouple, the gas port thermocouple, and the chamber thermocouple for a plurality of different ammunition round firing sequences for predicting the number of successive rounds of ammunition that may be fired before the firing chamber reaches a projectile deformation temperature.

A method of manufacturing a test ammunition round, the method comprising the steps of:

• providing a projectile that is compatible with a firing chamber for a firearm under test;
• boring a receiving cavity in a proximal end of the projectile;
• providing a case that is compatible with the chamber of the firearm under test, the case including a case passageway extending from a proximal end to a distal end;
• boring a case opening into in the proximal end of the case;
• providing a thermocouple and a lead wire electrically coupled to the thermocouple;
• one of brazing and soldering the thermocouple into the receiving cavity of the projectile;
• running the lead wire from the thermocouple, and through the case passageway of the case;
• pressing the proximal end of the projectile into the distal end of the case;
• providing a sleeve including a cylindrical outer side wall defining an axially extending sleeve passageway;
• forming a radially extending slot within the proximal end of the sleeve;
• running the lead wire axially into the sleeve passageway and radially out through the slot in the sleeve;
• and
• pressing the distal end of the sleeve at least partially into the proximal end of the case.

A method of measuring the temperature of a chambered projectile in a firearm using a test ammunition round, the method comprising the steps of:

• providing a firearm including a firing chamber;
• instrumenting a test ammunition round projectile with a projectile thermocouple;
• coupling the projectile thermocouple to a data acquisition system;
• firing a first plurality of rounds of ammunition through the firearm under test to heat the firing chamber;
• inserting the test ammunition round into the firing chamber;
• recording a first temperature profile of the projectile through the projectile thermocouple with the data acquisition system;
• removing the test ammunition round from the firing chamber;
• firing a second plurality of rounds of ammunition through the firearm under test to heat the firing chamber, the second plurality of rounds of ammunition being greater than the first plurality of rounds of ammunition;
• inserting the test ammunition round into the firing chamber;
• and
• recording a second temperature profile of the projectile through the projectile thermocouple with the data acquisition system.

A method of assessing a firearm comprising the steps of:

• providing a firearm including a firing chamber;
• instrumenting a test ammunition round with a projectile thermocouple;
• coupling the projectile thermocouple to a data acquisition system;
• firing a first plurality of rounds of ammunition through the firearm under test to heat the firing chamber to a first operating threshold temperature;
• inserting the test ammunition round into the firing chamber;
• measuring signals from the projectile thermocouple indicative of temperature of the test ammunition round within the firing chamber to determine the first operating threshold temperature;
• removing the test ammunition round from the firing chamber;
• firing a second plurality of rounds of ammunition through the firearm under test to heat the firing chamber to a second operating threshold temperature;
• inserting the test ammunition round into the firing chamber;
• measuring signals from the projectile thermocouple indicative of temperature of the test ammunition round within the firing chamber to determine the second operating threshold temperature;
• determining a deformation temperature resulting in a deformation defect of a projectile received within the firing chamber;
• determining a time during which the projectile can be exposed at the deformation temperature before the deformation defect occurs;
• and
• predicting which of the first plurality and the second plurality of rounds of ammunition that may be fired through the firearm before the deformation temperature is exceeded.