Priest 105 mm SP Gun

Scan supplied by Hanno Spoelstra

M7 105 mm Howitzer Motor Carriage The M7 was a self-propelled gun based in the M3 medium tank chassis. From April 1942 until August 1943, 3,314 M7s were built. From March - October 1944 another 500 rolled from the production lines.
Development of the Priest chassis followed that of the Medium tank series and thus it was powered by the Continental R975-C1 9 radial engine and was fitted with the M3's three-piece final drive housing (with the distinctive cut-out on the top right hand corner) and early style bogies. These were later replaced by the three-piece final drive housing as found on early Shermans and the heavy duty bogie with the top return roller offset to the rear. The machine gunner's pulpit was also improved.
The last production version M7 had a 1.5" mild steel lower hull. The M7B1 was largely identical to this production version, except that it was fitted with the Ford GAA V8 engine.

The M7 in Commonwealth service: the Priest 105 mm SP Gun In Commonwealth service, the M7 was designated Priest 105 mm SP Gun, with which the clerical name tradition established by the Bishop was continued. Under the Lend-Lease Program, 828 Priest were assigned to the United Kingdom. The first ones were rushed to North Africa where they were first introduced in action by the British at El Alamein.
Because the Royal Artillery wanted to standardise on the British 25 pounder gun, a replacement SP gun was designed. The Sexton 25 pdr SP Gun was designed along the lines of the Priest and production started in early 1943. The Sexton started replacing the Priest (shortly) before D-Day, this continued in Normandy. This left a number of Priests freed up for conversion on 2 August 1944 as at this time the Canadian/British self-propelled artillery units in North-West Europe were standardizing on the Canadian Sexton 25 pdr SP gun. Some units reverted from their SP role for the Normandy invasion, back to the towed 25 pdr guns.

Photos show that the Commonwealth Priests in Normandy were all fitted with three-piece final drive housings. They had either the early or the later style heavy duty bogies. Many, if not all, were fitted with Additional Armour on the hull sides.

Priest 105 mm SP Gun with Additional Armour

A deficiency of the first production version of the M7 105 mm HMC was that the ammunition stowed vertically in the ammunition racks was partially exposed above the side armour. On later production versions this was rectified by adding hinged armour plates which could be raised on the sides and the rear of the fighting compartment to protect the ammunition.

In British/Canadian service this deficiency of early M7s was rectified by adding fixed armour plates to the hull sides. The plates were fitted using bolts, slightly overlapping with the original side plates. The thickness of the plates is unknown, although thicker than the hull sides is unlikely. (On British Cruiser Tanks many sections of 14 mm plate was used, this is only slightly thicker than the 0.5" hull side so that would make a good guess.)

The picture on top of this page shows Priest SP Guns of 33rd Field Artillery Regiment in Normandy, June 1944. A sheet metal deep wading extension is fitted on top of the Additional Armour. Also, under the howitzer another sheet metal part of the deep wading kit is still fitted.

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