PT Expansion has been upgraded significantly in Fall 2007. Changes users of the previous version will notice include:

• Major improvements to the matching algorithm that allow users to match test data faster, more accurately and with more control over the process.
• The accuracy of the analysis has been improved particularily in cases where the experimental pressure vs. time data had relatively few data points.
• Experimental data has been separated from analytical predictions created in other Interior ballistics modules

This last change may be the most noticible to experienced users. The experimental pressure vs. time data used in PT Expansion is stored in a new location in order to preserve the analytical results from the other Interior Ballistics analyses. When you open the new PT Expansion, the PT table will be blank even if you had used the old version of PT Expansion with this projectile. Don't panic. Your old data is still available. Simply copy and paste the time and chamber pressure data from the tabular results tab to fill this table.