QuickStart is a short description of how SmartShot works with a few simple examples; a good place to start.
The SmartShot Manual describes the use of familiar input variables, i.e., muzzle velocity, temperature, range, etc., to compute firing solutions in terms Equivalent Hold Point (EHP) for the DTReticle. Additionally SmartShot computes firing solutions in terms of the barrel elevation and azimuth angles for traditional dial-up and grid reticles. SmartShot also computes spin drift, crosswind jump, boundary layer, Coriolis, near-field obstacles and others. The physics of spin stabilized projectiles in air under the influence of gravity on a rotating platform (Earth) is complex but to a great extent deterministic except for wind. So naturally the mathematics needed to describe the physics is also complex, thus SmartShot is complex. However, to a great extent, the user need not be concerned with this complexity because SmartShot is configurable by the user to provide the simple firing solutions needed for short range and the complex firing solutions needed for long range which might be deep into the subsonic regime. SmartShot supports these widely diverse firing solutions with toggles which turn on or off the effects of spin drift, crosswind jump, Coriolis, etc.
As an example of simplified complexity, SmartShot can compute air density three ways to accommodate the air data available to the user: 1) local pressure, temperature and relative humidity, 2) temperature, relative humidity and geographic altitude from a topo map or GPS unit and 3) a handheld weather station that reads density altitude directly.
SmartShot’s firing solutions are based on the ability of the bullet to retain velocity rather than the traditional ballistic coefficients. Firing solutions based on comparison to an obsolete 1800’s projectile which bears little resemblance to a modern VLD bullet are not sufficiently accurate for long range ballistics. Much more discussion of this often contentious topic is provided in the manual.
The Manual includes a detailed Table of Contents which is hyperlinked (Ctrl+click) to the relevant paragraphs.
200712 User Manual.docx
Since SmartShot uses Velocity Retention instead of ballistic coefficients a table of VR values for a number of bullets is provided below. If a specific bullet is not in the table the VR can be estimated using a conversion from either BCg1 or BCg7 to VRsupersonic. Use the VRsubsonic of similar bullets in the table. See the Manual paragraph 3.1.3.
200710 SmartShot Bullet VRs.xlsx
David Tubb’s Dynamic Targeting Reticle Instruction Manual is on-line at https://www.davidtubb.com/index.php?route=account/download/free&download_id=30