CAESAR: The Long-Range Proven 155 mm 52 Cal

Sub Title : Caesar consistently achieved very high accuracy in high temperatures

Issues Details : Vol 16 Issue 1 Mar – Apr 2022

Author : Colonel  Olivier Fort (Retired)- Nexter Systems

Page No. : 19

Category : Military Technology

: March 31, 2022

In its short service life CAESAR has had the unique opportunity to be battle tested in three very different operational environments albeit all three were hot and arid. After three years of not firing in anger, it is a good time to take a look at the platform’s most demanding operation in Iraq from 2016 to 2019.

CAESAR is the only 155 mm 52 Cal gun in the world to have fired more than 70% of 19,000 rounds above charge 5 and 6 in high temperatures often close to 50°C. In doing this, Caesar consistently achieved very high accuracy (the US artillerymen qualified it as a near precision artillery system, when in fact it was only firing unguided munitions).

The high proportion of long-range fire missions is due to several causes. During the move towards Mosul the authorisation to move artillery forward was delayed until only 52 Cal and rockets could operate. Secondly, long-range cannon fire missions were naturally assigned to CAESAR instead of the US 777 and M109 during some periods.

This long-range-heavy operation confirmed CAESAR’s excellent safety record, no accident occurred and no crew members were injured, despite regular prolonged long-range fire missions. A closer look at the statistics shows that some units in Iraq conducted over 50% of their missions at Charge 6 during their 4-5 month tour. Of note, all the operational rotations consistently fired around 90% of their fire missions at charge 4 or above, meaning above 39 calibre range. The longest fire missions recorded in combat were 36 km in Iraq and 37,6 km in Afghanistan.

This success is in great part explained by the fact that from the start, CAESAR was conceived by Nexter as a long-range gun. Among the main long-range features, but by no mean the only ones, are the robustness of the screw breech and the primer. When going from 39 Cal to 52 Cal Nexter shifted from the slide breech of the AUF1 and TRF1 to a new screw breech design. It was then assessed that at sustained, long range rates of fire, a slide breech could present noticeable safety risks. The ‘near high intensity’ operation in Iraq vindicated technical choices driven by safety and the requirement for precision. The US artillery extensive combat experience seems to have led to the conclusion that for its 58 Cal a slide breech is incompatible with current 52 Cal JBMOU charge ignition standards, but rather than adopting a screw breech, the US will adopt a charge solution with stub case destined to prevent leaks seen in several 52 Cal guns.

This invaluable long-range fire experience allowed the French artillery to extend its knowledge in all fields from training to tactics and maintenance. It enabled Nexter to conduct minor adjustments to further improve CAESAR’s long-range capability.

Very few in service guns ever have any opportunity to practice long range fire on limited peacetime ranges, and even less at sustained rates of fire and in very hot temperatures. Very often, long range is limited to experimental shoots with long-range ammunition. What Iraq taught us, however, is that very long-range firing needs to be based upon reliability and the certainty that the gun will behave consistently in terms of safely and precision in combat conditions in the 30 to 40 km range bracket. So far only CAESAR has proved this capability, with about 13,300 rounds fired at charge 5 and 6 in support of the Iraqi army. This proportion together with the number of rounds would have been even higher if at the time Illuminating and Smoke munitions had been qualified for Charge 6. This has since been addressed and Nexter has qualified both ammunitions types.

CAESAR’s own long-range record-breaking fire tests have so far involved VLAP (Very Long Range Artillery Projectile) trials at 57 km and Excalibur recently fired at 46km for its first mission. Lastly, the sensor-fused munition BONUS produced by BAE and Nexter in cooperation also proved itself with devastating effect on 17 occasions against armoured pick-ups, due to the successful technological and tactical combinations of the whole artillery system.

The author has been the Future Artillery programme manager for the past three years at Nexter. Up to early 2019 he was director of the capability and doctrine department of the French artillery.