Figure 1-36. Free Bolt Momentum Imparted After Unlocking.

velocity loss resulting from the effect of the combined initial compression of the barrel and bolt springs for the first 0.00334 second is equal to 1.118 feet per second, computed as follows:

V~Mr~ 50 Ml8WJ

The loss due to the combined spring constant K, as determined by the method of step 4 is only about 0.26 foot per second. This loss is so slight that it is not necessary to continue the process of successive approximation any further than step 5. Examination of the curves of fig. 1 34 reveals that the total recoil movement before unlocking is 0.0470 foot (0.565 inch) and the recoil velocity at the instant of unlocking is 19.2 feet per second.

4. Barrel motion after unlocking

Immediately after unlocking, the barrel strikes the buffer and its rearward motion is halted. Since the barrel weighs 40 pounds and is moving at a velocity of 19.2 feet per second, its kinetic energy is equal to

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