Posting a few ballistic files that shooters may find useful. Expansion Ratio is interesting, as it is the number of times the gas will expand in the total volume of the gun. it is simply case capacity plus bore volume divided by case capacity. The expansion Ratio number gives a indication of the efficiency of a cartridge. Generally a number below about 4 means that the cartridge is not as efficient as one with a higher number. Note that a few examples are: 222Rem 10, 22/250 6, 220 Swift 5, 22/06 4, 6mm BR 8, 308 9, 30/06 7, 300 Weatherby 5. Note that the most efficient cartridges are around 7 and up in number. This means that larger cartridges must burn more powder and may not produce much improved velocities along with increased barrel wear. When using the Expansion Ratio Calculator you measure the case capacity in grns of water to the base of the seated bullet and barrel length is measured from base of seated bullet to muzzle. You can calculate the case capacity in grns of water for seated bullet using the loss of water calculation in the Ballistic Calculations spreadsheet.

Equal SD calculator is very handy as it shows bullet weight required to match in any calibre. 

Included is a PDF showing approximate case capacities in grns of water, remember that you must subtract the seating depth loss to arrive at nett capacity to use Expansion Ratio and compare cartridges.

Hope that some of you find these files handy. 

Just discovered that I can't attach all my files to this post as they must be too large. Will post more forum topics to list the additional files.