The 1/92nd Field Artillery
We will not tell you how to build a bunker-hopefully the pictures will give you some idea-or how to fire a howitzer. We will however expose you to some of the techniques employed to keep the voracious appetite of a 6 _ ton Pig quenched and how to keep said Pig from escaping the pit and keep it pointed in the right direction.
Depending on where you were within the country of Vietnam would have a major impact on the layout of the gun pit. If you are at your Base Camp where all the officers from Battalion are based, where all the Generals come to visit, etc. your gun pit would look very different than a gun pit on a small hill top LZ somewhere where everything you have has to be flown into you. When you were in the field functionality took precedence over ascetics. If you were in a unit that was under the 52nd Artillery Group Vs 41st Artillery Group you could have a different layout as well.
The Basics however were the same and the expectations of most Battery Level officers were similar i.e. no matter what time of day you occupied the firebase or LZ you had to have the gun laid and at least 3 layers of sandbags over the top of the Ammo, Powder, Fuzes and your sleeping area before you could lay your own head down. If you were lucky you would have some infantry to help with or pull guard duty... if you weren't, it would be a very long day because you would have to develop and man perimeter defenses. That however is a different story.
The basic components to a gun pit are fairly easy to list (you can refer to the picture above which refers to the numbers below) but not necessarily easy to fabricate. In some places we had access to lumber with which to build walls to support the roofs of the ammo and powder bunkers. In other areas we had to fell trees to get the lumber. Improvising ways from discarded ammo pallets and powder canisters was normal "SOP" limited only by your imagination. The one thing we always took with us (besides sandbags) no matter if we were airlifted or roadmarched was sheets of PSP (perforated steel planking) to support the sandbag load for the roofs of everything from ammo to personnel. Most gun pits had a bunker for the ammo 1, another for the powder 2, one or two for fuzes 3,and one for the ammo that was maintained separate from the others. To keep from making a mistake in the heat of the battle (most missions were at night with reduced lighting), the Firecracker and Willie Pete 4rounds were stored in their own mini bunker or a separate portion of the main ammo bunker. If you had a primary and secondary field of fire i.e. north and south, you could build your ammo and powder bunkers on opposing sides of the gun pit (east and west) and most of the time you could fire without impeding the preparation of more ammo. The Howitzer in the picture above is C Btry's Gun 4 (L-18) at Phu Nhon and it is facing northeast toward FSB Weigt Davis, the other Howitzer in the platoon (Gun 3) is facing south toward FSB Lonely. Also referenced in the picture above are items used for Fire Control... they are: Azimuth markers 5 for roughly pointing the Howitzer in the correct direction, Collimator 6 and Aiming Post 7. The latter two were used by the Gunner to maintain the Howitzer in the correct Deflection during fire missions. These items will be explained in greater detail in the howitzer section under firing.
How do you fit 6-155mm Howitzers on the head of a pin? Take a lesson from Firebase 6...notice the common walls of the Ammo and Powder bunkers of one pit become the walls of another pit. Notice also the use of"Blast Walls" in front of the ammo and powder bunkers... where time permitted or incoming was a certainty these walls were a must.