A pneumatic sample clamp is used to secure the specimen in place for ease of operation and operator safety. The operator needs to simultaneously activate dual switches mounted on either side of the instrument to engage the clamp and initiate the free falling dart. In addition, the dart drop tester provides a dual clamping sequence. The first phase utilizes low-pressure to safely clamp the sample followed by a high-pressure clamp prior to testing. The final phase of the test is completed with an automatic dart release.