Feb 8, 2006
4952 Windplay Drive, Suite C
El Dorado Hills, CA 95762
I have completed the ballistic tests you requested and the test-result data is included on the attached pages. Testing consisted of measuring the velocity and pressure produced by 28-ga ammunition fired in a 16-gauge test gun and 20-ga and 28-ga ammunition fired in a 12-gauge test gun. The sub- gauge ammunition was held in Gage-Mate adapters.
The velocity figures from shots fired in the 16-gauge test gun are instrumental at 4 feet from the muzzle. A correction factor of -46 ft/sec was app1ied to conform to the results determined by firing the test gun with SAAMI 16-gauge reference ammunition, lot # 16F-105F. In the 12-gauge tests the velocity figures are instrumental at 6 feet from the muzzle. A correction factor of+11 ft/sec was applied to the measured velocity, to conform to the results determined by firing the test gun with SAAMI 12- gauge reference ammunition, lot # 12T-109R.
The 16-gauge pressure readings were obtained by use of a strain-gage sensor mounted at 3 5/16 inches from the breech face of the 16-gauge test gun, which is just in front of the forcing cone. This gun has a 2 3/4-inch chamber. The Gauge-Mate adapters are 2.8” long. Mounting at this location was done to avoid placing the gage on the tapered cone area. Mounting it to the rear of the cone would have placed it over the adapter itself, which would lead to falsely low pressure readings.
The 12-ga pressure readings were obtained by use of a strain-gage sensor mounted at 3 inches from the breech face of a 12-gauge test gun, which has a 3-inch chamber.
An Oehler Model 43 Ballistic Laboratory and an IBM ThinkPad computer were used to process the data. The pressure data has no correction factor applied, as there is no standard reference-load pressure data supplied by SAAMI for down- bore locations.