[404] Official records are at variance on this point. The 2/5 command diary indicates that the battalion continued the exercise on 16–17 April, returning the latter date. The 5th Marines report categorically indicates that MARLEX XX was cancelled on 15 April, because of the weather. Not long afterward a training exercise involving UNC personnel got underway when the 5th[405] and 1st Marines, together with the artillerymen, combined with the Army, ROK, and Commonwealth Division on 20 April for a four-day I Corps command post exercise (CPX) EVEREADY GEORGE, not far from Seoul. [405] Now under a new regimental commander, Colonel Tschirgi, who had joined the 5th Marines on 14 April, succeeding Colonel Walt, newly assigned division G-3. Along the division front the war was still a daily survival contest, despite the promising outlook at Panmunjom. The most ambitious attempt by the Chinese during the month took place over a three-day period in the right regimental sector, not long after the 7th Marines had moved to the MLR. On 9 April, following a heavy two-hour ballistic downpour of 2,000 rounds of enemy mortar and artillery, a reinforced company of about 300 Chinese soldiers launched a strong probe against Carson at 0345. Attacking in two echelons, the enemy approached from the direction of Arrowhead on the north and the Reno ridgeline. In an hour’s time, the enemy had reached the Marine trenches and protective wire, at some places, and was being unceremoniously repulsed by the 1/7 detachment at Carson. For an hour and a half a heavy fire fight raged at the outpost while intruders and defenders battled at point-blank range to settle the dispute. A reinforcement platoon, from 4/2/7, dispatched from the MLR at 0530, made it as far as the newly established Marine outpost at Elko, about 400 yards southeast of Carson, before being held up by a heavy shower of mortar rounds, and small arms fire. Tankers from the Company A direct element[406] plus a section (two tanks) from the regiment’s armored platoon leveled their lethal 90mm fires to discourage the enemy, as did the defender’s barrage of 60mm, 81mm, and 4.2-inch mortars. [406] Throughout the three-day action, gun tanks from Companies A and B (the forward reserve unit) and the regimental antitank company fired a total of more than 1,469 90mm shells to neutralize enemy positions and weapons.