The pressure readings from the Model 43 system are relative for that strain 9 gauge installation on that gun only. It's important that the user assume a certain degree of responsibility for the resulting pressure readings of the Model 43. It's imperative that the strain gauge be installed exactly as indicated in the instructions received with the unit. If the strain gauge is not installed properly, or if the wrong kind of glue is used, for example, it's possible to produce lower than actual pressure readings. It's imperative that the user back off by 20 percent from the level when these signs originate and to check the installation of the strain gauge and connecting wires, along with the operation of the entire system.
Outside diameter is needed for computing pressures with the strain-gauge system.
Again, Oehler has gone far beyond the normal velocity clocking that we're used to. Near the muzzle the Model 43 utilizes a conventional three-screen setup with the Oehler Proof Channel. The difference is a cable that connects to a second set of downrange screens or an acoustic target. Either can be used, depending on the setup you have. Since the acoustic target is new, let's assume you're using it downrange.