Challenger 1 Main Battle Tank, vol. II

The gunnery phase of the trial was designed to show the Egyptian team the accuracy and effectiveness of the L11A5 gun and the standard ammunition types used. The ammunition natures employed consisted of HESH (High Explosive Squash Head), APDS (Armour Piercing Discarding Sabot), APFSDS (Armour Piercing Fin Stabilised Discarding Sabot) and SH/PRAC (Squash Head Practice). These were to be fired from a static vehicle engaging static targets, then from a static vehicle engaging moving targets and finally from a moving vehicle engaging moving targets. The engagement sequences were also designed to show how the trunnion tilt compensator in the gunner’s sight could compensate for the tank’s armament being fired on a side slope. Weather-related problems beset the gunnery phase, including the cancellation of a night firing sequences, all of which would not seem to indicate that the Challenger was an all-weather weapon system capable of operating 24 hours a day. One would wonder if the Egyptians had developed misgivings by this stage. The coaxial machine gun and smoke discharger drills were not demonstrated either.

This very soberly marked Challenger was probably photographed a few years later, but is also from the Royal Hussars. [John Cook]

A crew from the R.A.C. fired most of the practice engagements for the trial although an Egyptian gunner did fire some of the serials. The DS/T firing involved firing eighty rounds at fixed and moving targets, at ranges up to 2500m the hit rate was 92.5%; the rate against a moving target was astonishingly 100% and 85% was achieved from a moving tank against a moving target. The firing of APFSDS munitions gave acceptable accuracy scores but the main issue was that despite the grouping of the rounds fired being very close, the actual mean point of impact was very low on the target. It was accepted that the grouping did show how accurate the L11 gun was. The SH/PRAC firing trials had a very bad start, firing twenty eight rounds- and scoring no hits, which caused consternation. The ammunition batch was withdrawn and deemed faulty. With a new batch of ammunition things improved and the hit rate was deemed acceptable, but first impressions may have counted. The R.A.C. crew showed that it was possible to load with the standard separate bagged charge ammunition at a commendable rate of 8 rounds a minute consistently. Two serials fired by the visiting Egyptian gunner both had a 100% hit rate.
The final automotive phase then took place at Catterick Garrison in North Yorkshire, and was designed to show the Challenger’s impressive obstacle crossing capability; but looking at the report results, the course chosen seems to have been uninspired. The Challenger crossed a series of obstacles which did not trouble it, having crossed more arduous ones during a demonstration in the Middle East earlier in the year. That concluded the trials and although the hospitality must have been laid on thickly, the actual sequence of events (one would suspect) probably did not impress the visitors. Cancelling trials for bad weather seems irregular, and foolish in light of the need to prove a weapon’s capabilities…which along with the accuracy issues with the practice ammunition probably made the Egyptians decide against buying the Challenger 1. It would not be last time Vickers bungled its chances of selling a British tank.
The Challenger’s first real test in British hands was waiting in the form of the NATO tank gunnery competition known as the Canadian Army Trophy (CAT) and the end result would be a scandal. The Royal Armoured Corps was keen to restore its pride after the Royal Scots Dragoon Guards had come last in CAT 85 equipped with the Chieftain, so CAT87 was seen as the perfect opportunity to “sell” the Challenger. Sadly all did not go to plan. Much has been written about the actual event and space precludes a full write up here (an excellent account is available in the Osprey New Vanguard on Challenger 1 by Simon Dunstan), so suffice it to say that the Challenger came a very poor last in the event and of the many myths that have grown around it, some have some basis in truth.

Here we see 06 SP 42, a later prototype. Some of the prototypes endured as test vehicles and as sales platforms for Royal Ordnance for a few years in the mid 1980s. [John Cook]

Although the Challenger hit more targets than most during its battle run, its engagement times were painfully slow compared to the hunter-killer equipped Leopards and Abrams. The slow engagement times were blamed by many in the defence press on the 3-piece ammunition the British used, but in reality the problems were centered on the IFCS system and the turret’s poor ergonomics. In essence the Challenger was the wrong tank at the wrong time, trying to win a competition against tanks equipped with stabilised gunnery sights and panoramic commander’s sights. The Challenger went to CAT 87 using more or less the same fire control system as Chieftain had before it due to its Shir 2 lineage, the commanders sights on the Challenger had been tweaked to try and help it in the competition: but with sights only stabilised in two axes it was never going to win.