In 1940 the British Army concluded that the only heavy howitzer available to it, the First World War-era BL 8-inch howitzer, had insufficient range for the conditions of the Second World War. As a stopgap the decision was made to re-line the barrels to a smaller calibre and develop a new range of ammunition to achieve the desired ranges.[1][2][4]
Marks I–IV
The 8-inch barrels were re-lined to 7.2 inches (183 mm) and the old carriages were retained although the original steel rimmed wheels were replaced with new pneumatic balloon-tyre wheels, as was consistent with the motorisation of the British Army. The new four-charge ammunition increased the range to 16,900 yd (15,500 m), but when fired at full charge the recoil caused the weapon to rear violently and jump backwards. To help counter this, two wedge shaped ramps were placed behind the wheels although the gun could sometimes still jump over them, presenting a hazard to crews. Marks I–IV differed only in the original 8-inch barrel used and the type of conversion; some barrels and carriages were also supplied from US First World War stocks.[1][2][5]
Mark V
In 1944 several 7.2-inch barrels were placed in the US Carriage M1 used by the 155 mm Long Tom already in use by the British Army, becoming the BL 7.2-inch howitzer Mk V. Few Mk Vs were produced and it was never issued to batteries, as it was apparent that the Carriage M1 was capable of accepting greater recoil forces.[1][2]
Mark 6
The BL 7.2-inch howitzer Mk 6 (there was a shift from Roman numerals) retained the Carriage M1 of the Mk V but had a new 7.2-inch 6 ft 5 in (1.96 m) longer barrel than previous marks and a fifth charge was added to the ammunition. The longer barrel and extra charge provided an increase in range to 19,600 yd (17,900 m) and the new carriage also provided a far more stable platform, greatly increasing accuracy.[6] The Mk 6 was considered a highly effective gun and it was retained in service after the war.[1][2]
Use
The original marks performed well. The first 7.2-inch howitzers were issued to batteries from mid-1942 and used in action in North Africa and in 1944 following the Normandy landings. In Burma they were provided as a pool of two guns per corps and used by Regiments as required. By the end of 1944, most of the earlier marks had been replaced by the Mk 6.[1][2] The usual gun tractor for the 7.2-inch howitzer in the early war years was the Scammell Pioneer, although this was never available in sufficient numbers and from late 1943 the Pioneer was supplemented by the Albion CX22S.[7] The BL 7.2-inch howitzer was usually employed in two four-gun batteries (alongside two four-gun batteries equipped with the 155 mm Long Tom) of "Heavy" regiments of Army Group Royal Artillery (AGRA) units, providing heavy fire support for British and Commonwealth troops. The Mk 6 remained in British Army service until the early 1960s.[2][3][8]
Indian Army service
In 1957, Indian Army raised 60 Heavy Regiment from the erstwhile J&K Bodyguard Cavalry. The unit was unique in its composition of four batteries with four Mk 6 BL 7.2-inch Howitzers in each battery, unlike the standard three-battery (six guns each) composition of other Indian artillery regiments. The guns of 60 Heavy Regiment saw combat in the 1965 and 1971 wars against Pakistan. In the early 1990s 60 Heavy Regiment was converted to a field regiment and the guns were passed on to 61 Heavy Regiment. They were finally retired from service by the late 1990s.
^Gen Sir Martin Farndale, History of the Royal Regiment of Artillery: the years of defeat, Europe and North Africa 1939–1941, London: Brasseys, 1996, ISBN1-85753-080-2.
^Williford, Glen M. (2016). American Breechloading Mobile Artillery, 1875-1953. Atglen, Pennsylvania: Schiffer Publishing. pp. 108–111. ISBN978-0-7643-5049-8.
