The shorter length of the 8" howitzer M1 or M2 is immediately apparent when it is compared with the 155mm gun M1A1 or M2 found on the 155mm GMC M40. The drivers' cupolas are visible from this angle, along with the brush guards for the missing headlights and siren and the shield for the crew beside the howitzer mount.
The rear platform is lowered, giving the howitzer crew extended working room when servicing the piece. (Picture courtesy Tank and AFV News.)
A view of the hull front gives further details of the drivers' cupolas and the racks on the hull front intended to store extra track blocks. The cupolas were fixed, but the doors with the periscope mounts could be rotated. The top of the howitzer travel lock is missing from this machine, but if present we would see that it was indented on both sides with different sized radii so that it could accommodate both the 8" howitzer and the 155mm gun simply by being reversed.
The rear of the vehicle is labeled in this image. (Picture from TM 9-747 Sep 1947.)
The top of the vehicle is shown here. A. Spade. B. Ramp extension. C. Ramp. D. Loading rack. E. Crew seat. F. Loading tray. G. Panoramic telescope M12. H. Telescope mount M18A1. J. Universal shell rack. K. Carburetor air cleaners. L. Recoil pump. M. Mattock. N. Ax. P. Left fuel tank filler cover. Q. Track adjusting wrench. R. Crowbar. S. Engine oil tank filler cap cover. T. Shovel. U. Fixed fire extinguisher dual pull cable exterior shield. V. Driver's cupola doors. W. Driver's direct vision blocks. X. Blackout driving light. Y. Klaxon. Z. Front fender. AA. Track link rack. AB. Traveling lock. AC. Headlight. AD. Antenna. AE. Searchlight. AF. Assistant driver's cupola door. AG. Starting crank. AH. Mattock handle. AJ. Sledge hammer. AK. Right fuel tank filler cover. AL. Engine compartment cover grille. AM. Lifting hook boom. AN. Cal. .30 carbine mounting brackets. AP. 8 in. howitzer. (Picture from TM 9-747 Sep 1947.)
The complete travel lock is shown here. Note that the upper half collar is reversible for the 155mm ordnance on the M40. (Picture from TM 9-747 Sep 1947.)
The assistant driver's cupola door is pointed to the right rear, while the driver's faces more to the front. An antenna mount is welded behind the right-side headlight cluster, and a shaft for mounting a spotlight can be seen next to the assistant driver's cupola. Clips for stowing a tow cable are attached to the hull roof, hull front, and final drive and differential cover.
Outboard of and behind the driver's cupola on the hull roof is the guard that housed the external fire extinguisher handles, and another tow cable clip can be seen in front of the fire extinguisher handle guard.
Details of the howitzer mount can be seen in this view, along with a fuel filler cap in the hull roof behind the driver.
Another angle of the howitzer mount and left-side shield for the crew is provided here.
A similar view of the right side of the mount is shown in this picture.
The wider hull compared to the tank from which it was automotively derived forced the use of longer connections for the final drives.
Casting adapters were welded to the wider hull sides in order to mesh them with the final drive and differential housing. The bolts on these extensions were angled forward to make up for the steeper slope of the propeller shaft necessitated by moving the engine forward.
The longer hull also saw increased spacing between the suspension bogies versus the tank.
The rear platform is lowered, allowing an overall look at the fighting compartment. (Picture courtesy Tank and AFV News.)
Underfloor stowage can be seen as well as the howitzer's elevation arc and shielding for the crew near the howitzer tube. A longer grated platform was able to be pulled out from under the solid platform to provide more working space for the howitzer crew. Details of the stabilization spade, including a pulley to assist in its retraction, can be discerned.
Stowage in the left side of the fighting compartment can be seen here.
Air cleaners for the radial engine were mounted at the front of the fighting compartment to either side of the ordnance mount.
Vertical ammunition racks that could stow either 155mm or 8" rounds were installed in the floor in the front corners of the fighting compartment.
The demilitarized howitzer breech is evident in this view, along with the sight mount on the left of the howitzer mount and the traversing handwheel mount below this. The elevation handwheel would be attached to the mount on the opposite side of the traversing handwheel.
The open breech for the howitzer M1 is illustrated here. The complete howitzer weighed 10,240lb (4,645kg), the tube was 202.5" (514.4cm) long, and the howitzer could fire a high-explosive shell to 18,510 yards (16,930m). (Picture from TM 9-747 Sep 1947.)
The mounted sighting devices are detailed in this picture. (Picture from TM 9-747 Sep 1947.)
The reinforcing members of the spade and the rollers that run along the bottom of the crew's platform are highlighted in this image. (Picture courtesy Tank and AFV News.)
The size of the vehicle and the working space provided by the folding platform can be seen in this image where the crew is present. (Picture taken 13 Aug 1952 by Kelemanik; available from the U.S. Army Center of Military History.)
