Downloads This page contains a selection of downloadable information. Spreadsheets to calculate various firearm figures such as bullet spin and energy to PDFs containing useful firearm information. This simple spreadsheet allows you to enter the twist rate of your barrel and bullet velocity and calculates how fast the bullet will be spinning as it leaves the barrel. This spreadsheet allows you to enter bullet weight in grains and velociy in feet per second and calculates the bullet energy at the muzzle. This spreadsheet coverts speed in feet per second to Mach number, based on being at ground level at 15c. Home Office Firearms Law Guidance to the Police 2002. VihtaVuori Reloading Guide, Edition 6, 2008. Accurate Powder Reloading Guide, Edition 3.2. To have cool reticle 'car' for your TomTom, just download the bitmap and copy it to the '...art/cars' folder of your satnav. Go into preferences and choose your 'car'. For some reason, it only works with the 3D view... Duplex reticle for your TomTom. German reticle for your TomTom. Taget dot reticle for your TomTom. Half duplex reticle for your TomTom. Range finding reticle for your TomTom. Mildot reticle for your TomTom.