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Internal Ballistics


Testing of primer performance ultimately requires using ammunition fully loaded as it would be used in a given application. However, it is also desirable to have a method to test and compare primer performance independently of a given cartridge and load. This removes confounding effects of powders, bullets, neck tension, case capacity, bore friction, etc. so that performance of different primer designs can be compared more directly as well as with field performance in complete cartridges.


BTG Research developed a method for directly comparing primer performance. High speed pressure transducers are used to measure the pressure wave produced by impact detonation of a primer loaded in a cartridge case without any bullet or powder.  This method allows us to produce objective, quantitative answers to questions such as:

  • How does the peak pressure and positive pulse duration vary within and between primer types and brands?
  • Does sorting primers by mass reduce the amount of variation in performance?
  • How does the performance of lead-free primers compare with common commercial primers?
  • How much does primer performance affect field performance of ammunition?


Other areas of internal ballistics work include quantifying barrel friction, testing bullet coatings, and developing custom loads for specific applications.






Measuring barrel friction in the 5.56 mm NATO

Comparing blast pressure variations of lead styphnate based and diazodinitrophenol based primers

High-speed measurement of rifle primer blast waves.

A method for testing bullets at reduced velocity


External Links


International Ballistics Society website