About 11 o’clock, the heavy guns of 305 of Eggewaertscappelle fired their first shot on Leugenboom, while the gun of Burg Molen continued its demolishing and blinding work on the enemy’s observation-post. A little while after the guns of Coxyde-Bains entered in action in their turn against Tirpitz battery. The observation of these firings were both terrestrial and aerial.
The firing program was continued the following days when the weather was favourable for observation.
On the 25th of May, an aerial photograph of Leugenboom position was taken. It did not disclose the least damage to the concrete block, but its clearness sufficiently noted the gun carriage not yet armed, in the centre of the honeycomb which formed the platform.
In order to parry, as might be the case, to a more accurate enemy counter-battery, the railway battalion built or layed out sucessively several sites for heavy artillery firing. It is so, that two sites on the switch point of Eggewaertscappelle, a third at the station of Moerhoek and a fourth on the point of Isenberghe, served as reserve, and were occupied in turns.
The Leugenboom heavy gun entered in action the 27th of June 1917. Between 5 and 10 o’clock, it bombarded Malo-on-sea and Dunkirk. This first action made numerous victims. The shells were of 380 mm.
One shell, amongst others, the first, it is thought, fell on the Casino of Malo, where the general staff of the XVth British army corps was established: it made twenty four victims, eleven dead and thirteen wounded.
In July 1917, there were several bombardments to be noted on different objectives: Furnes, Dunkirk, Coxyde, Forthem and Alveringhem.
The bombardments of Dunkirk, threatening to become very frequent, alarmed the authorities, and it was decided from the 19th of July 1917 to create two direct telephone lines at different courses which would join Dunkirk to the Pervyse railway station observation-post, which was particularly well situated.
The starting shots of Leugenboom, heard at the railway station at Pervyse, were in that way instantly communicated to Dunkirk, where the reception posts gave the alert to the town by powerful horns and other alarm engines, thus permitting the population to take refuge in the concrete shelters specially built for that purpose.
In spite of the well studied counter-battery, the Leugenboom gun still continued firing. The lulls, which lasted often long time, gave the hope that a positive result had been obtained. Then after a lapse of one and sometimes two months, the rage of the Germans revived and Dunkirk was again subjected to further attacks.