Kinematic Analysis of the M231 Firing Port Weapon.

The firing characteristics of a new M231 Firing Port Weapon were checked while firing M196 ammunition loaded with ball and IMR type propellants. Measurements of muzzle velocity and rate of fire were made during these tests. The average muzzle velocity for the M196 ammunition loaded with ball and IMR type propellants is about 914 ms. The average rate of fire for the M196 ammunition loaded with ball propellant is about 1255 rdsmin which is about 50 rdsmin higher than the average rate of fire for the M196 ammunition with IMR type propellant. A complete kinematic study was also made on a new lubricated weapon while firing M196 ammunition loaded with ball and IMR type propellants. Displacement versus time of the bolt carrier and the striker were measured using electro-optical displacement followers, Optrons, during firing of the test rounds. Pressure versus time in the bolt cavity was measured using a Kistler 601H Pressure Gage during firing of the test rounds. A sensitivity study was also made on a new weapon while firing under the following test conditions 1 The weapon was fired completely dry with no lubrication using M196 ammunition loaded with ball and IMR propellants 2 The weapon was fired with ammunition and weapon conditioned at 225.8K and 341.5K using M196 ammunition loaded with ball and IMR propellants 3 The weapon was fired using M193 ammunition from Lot No. LC4-85. Displacement versus time of the bolt carrier, and pressure versus time in the bolt cavity were measured during firing of the test rounds. Author