Drawing Number: 21105
Revision: NR
OPERATION MANUAL FOR
BALLISTICS PRESSURE SENSOR CALIBRATION ADAPTOR
FOR AMMUNITION TESTING
Model 090B
1
1.0
INTRODUCTION
The Series 090B Calibration Adaptors are designed
to facilitate calibration of the Model 117B Conformal
Pressure.
An actual empty cartridge case is pressurized with
precisely known hydraulic pressure and the
corresponding output of the sensor is read at each
pressure point to full scale.
2.0
DESCRIPTION
Refer to Drawing No. 090-2 -90 included as part of
this manual.
The Model 090B Adaptor Assembly consists of a
pressure chamber (Item 1) a pressure chamber
adaptor (Item 2), a cartridge case retainer (Item 3),
and a retaining nut (Item 4).
The pressure chamber adaptor (Item 2) contains an
O-ring to affect a pressure seal when the adaptor is
pushed into the cartridge case mouth. The opposite
end of this item is designed to mount directly into a
standard mounting port for the PCB Models 118A,
108A, 119A and 109A pressure sensors. This feature
precludes the need for high pressure fitting, tubing,
etc. thereby, keeping the total pressurized volume to a
minimum.
3.0
INSTALLING THE SENSOR
The sensor is installed in the empty pressure chamber
(Item 1) so that the flushness of the curved diaphragm
with the I.D. of the test chamber can be observed.
Before installing the sensor into the Model 090B
Adaptor, read the installation instructions supplied
with the specific sensor for which this adaptor is
designed.
Follow these instructions carefully paying particular
attention to the depth adjustment. The rotational
alignment is automatically controlled by the
alignment device incorporated in all 117B Conformal
Sensors.
4.0
INSTALLATION OF THE
CARTRIDGE CASE
(Refer to Installation Dwg. No. 090-2 -90)
It is important that cartridge case selected for
calibration be identical in all respects including
material, to the lot of ammunition undergoing test. It
is advisable that the test unit be selected from the
same lot as the ammunition under test for greatest
accuracy of test results.
For small arms cartridge cases, it is necessary to use a
case with the primer in place, but fired.
Note: Do not use a cartridge case with an unfired
primer or a case which has drilled holes.
If a sample cartridge is a loaded round, remove bullet
and powder, then fire the primer.
On certain calibers an O-ring is provided in the
cartridge case retainer (Item 3) to effect a pressure
seal at the boltface end of the case.
Inspect the boltface surface for irregularities or
imperfections in the area of this O-ring, which could
preclude a pressure seal.
Note: For shotshell installation, consult enclosed
drawing for necessary modification to the empty
shotshell case. The case must be cut to a specified
overall length to fit properly into the calibration
fixture due to inconsistencies in the designs of the
various makes of ammunition.
4.1
STEP-BY-STEP INSTALLATION
PROCEDURE
1. Remove Items 2, 3, and 4 from chamber body
(Item 1).
Note: For metallic cartridges, it is extremely
important that the mouth of the cartridge case be
chamfered to allow easy entry of the O-ring on
the pressure chamber adaptor. This operation is
easily performed with a hand held 90°
countersink or a sharp de-burring tool. If this is
not done, O-ring life will be drastically
shortened.