Installation Instructions for the M1091 M109Al/M115/M110 Howitzers and M107 Guns (cont)

TM 9-6920-361-13&P

Step4: Place the obturator spring over the adapter.

Step 8: Remove the elevating arc from the gun barrel by

removing the two mounting screw.

Step 5: Insert the adapter (top up) in the breech-block.

Step 9: Attach fine thread across the four witness marks

Step 6: Place the washer on the adapter. Tighten the

on the end of the tube by using a rubber band. Also

nut all the way down, then loosen it one turn. The

place boresight strings on the muzzle of the howitzer.

loosening of the nut allows the breech to be closed fully.

Step 7: Remove the four head cap socket screws and

Step 10: Place the gun barrel in the adapter and engage

the

adapter

cap.

the barrel trunnions with the adapter slots.

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