Internal Ballistics Home Page

Theory

Warning: the theoretical formulas and programs presented below cannot be used to calculate loads for small arms, due to their high sensitivity to initial conditions such as the bullet pull force, chamber throat length variations, bullet engraving forces, and powder grain burn rate deterrent coatings, without verification from empirical measurements such as those presented in reloading manuals. Large guns/cannons do not suffer from the same caveats and are easier to model.

• Le Duc Model
• Powley Computer
• Classical Theory Tutorial from Coppock's Model Manual
• Analysis of a Pressure Curve
• Velocity vs Case Capacity and Barsness' rule of thumb
• Mathcad Sheet of Coppock's Model

Products

Internal Ballistic Modeling Software:

• Le Duc Model  Le Duc program for DOS.
• Coppock's Model now shareware with more functionality (DOS)
•  NABM for Windows beta version,  with graphing capabilities. Use 1024x768 large fonts.
•  NABM without the BDE  Use this if you already have the Borland Database Engine installed.
• Strain 3.0fWindows 95 Program for computing pressures from strain and gun chamber dimensions. This version adds statistical calculations for results, and plots pressure curves using the Heydenreich Model - given a measured peak pressure and muzzle velocity. Now with LeDuc Model and graph printing capability. Also with Strain to Pressure conversion graph (printable).  Now works with piezo. efficiency of .1 to .55.
• Strain 3.0x version information

Chamber Pressure Instrumentation:

Featured in Aug '97 Handloader Magazine!

Tactical Shooter - July '98, ".408 Cheyenne Tactical (TM)- A Novel 2,000 Meter Tactical Cartridge", John Taylor

Wildfowl - Aug/Sept '98, L.P.Brezny - Shotgun load measurements

Wildfowl - Oct/Nov '98, L.P.Brezny - Review of system

Tactical Shooter - Jan '99, "The .338 Lapua Magnum Cartridge: Origin, Development, and Future", John Taylor

Gun Digest 2000 - Reloading Column - Larry Sterett

Tactical Shooter - May 2000, ".408 Cheyenne Tactical(TM) - A Novel 2000 Meter Tactical Cartridge part 2"

American Rifleman - July 2000 - Reloading Column - L.P.Brezny

Tactical Shooter - Oct 2000, "MAG-15 Using the .45 Professional Cartridge", J. Taylor

Now for the first time here is an inexpensive meter that will allow you to measure peak chamber pressures more accurately than any other method except direct piezo measuring devices that require a special pressure barrel. The meter connects to a small gage that is glued to your gun barrel. This self contained system requires no computer!

New! No soldering required - No sanding required on blued guns!

• 
• bigger picture
• summary operating manual
• detailed manual
• specs
• Strain to Pressure Conversion Formulas
• strain gage application notes
• sample traces with Radio Shack probescope

Links to gun related products:

Links to instrumentation, chronographs and pressure measurement products:

• Oehler Research Inc. chronographs, Model 43 Strain/pressure/chronograph
• Extech Handheld scope with pretrigger - $299, PC link available
• Velleman PC64i scope Nice 2 channel 20Mhz with pretrigger - at Radio Shack on sale sometimes
• Link Instruments Very nice digital oscilloscope for PC DSO-2102
• Allison Technology Corp digital oscilloscopes for PCs, distributors of Picotech products
• Pico Technology Limited more digital scope units for PCs, (check out ADC200/20)

Links to mathematical modelling software:

• Matlab - The real thing, but expensive.
• Scilab - A free alternative to Matlab.  Quite nice.
• Mathcad - Not too expensive, must have for simple units handling.
• TKsolver - Excels at simultaneous non-linear equation solving.

Change Log last mod. 30 Nov 01