Jimmy:

I found the HGDT application, it doesn't seem to work in 64bit computers as it has components compiled for 32bit computers

Everything in the HGDT parameter set has to be set right. Here's an example for a 3" x 36" "monogun". The ammo mass and friction values are WAGs. On the right is a screenshot of HGDT, on the left is an Excel sheet where I collected data as I swung the chamber to barrel composition with a total leng...