I want everyone to put on their thinking caps. This is about chronographs.
While doing some research about an Ontario gunsmith, I came across a letter written by Jack O'Connor about some cartridge tests using Vernon Speer's chronograph. I presume it was the company chrono. It was called the "Potter Counter Chronograph". This was probably made by the Potter Instrument Company.
Does anyone have any information about this chronograph and the company? It appears to be something that would have been used in the late 1940s into the 1950s. References to Potter Chronographs were made in various military documents of the time.
I believe the Potter chronograph worked just like more recent models--measuring the time of flight between breaking two screens placed a precise distance apart--except it used vacuum tubes before transistors (solid state) were invented. It cost around $5,000 in the '50s, which meant that individual shooters simply could not afford one. Back then a lot of wildcatters had exaggerated opiniions of he velocities they were getting and even some manufacturers of factory ammo "lied" (to put it delicately) about the velocity of their products.
Modern chronographs use a crystal oscillator as the time base. The Potter probably used a circuit called an "astable flip flop," consisting of two vacuum tubes and some other components, which would have meant that it was not as accurate due to temperature changes. Needless to say, the Potter was very large and cumbersome.
