On 19 July 1963 Colonel Stanley I. Hand relieved Colonel Wilkins as Commander, 306th Bomb Wing and Colonel Wilkins became Vice Commander. The Wing continued its primary mission of deterring a nuclear attack by maintaining nuclear ground alert with eight B-52Ds out of 15 assigned, and eight KC-135As out of 16 assigned. The B-52Ds were equipped with the AGM 28, "Hound Dog", long range air-to-ground nuclear missile that could be delivered from high or low altitude. The primary method of delivering various types of nuclear gravity bombs was from low altitude using the B-52s radar bombing and navigation system. The aircraft terrain avoidance system aided the crew in flying low altitude in all weather conditions to reduce the effectiveness of Soviet radar. The B-52D ECM system and four 50 caliber radar directed tail guns provided for defense against enemy antiaircraft guns, missiles and aircraft during penetration of Soviet airspace.
Alert change over occurred twice weekly resulting in tours of four and three days. Bomber crews were located in the alert facility on the South West end of the runway while the tanker crews were located in a converted barracks near the Officers Club. No-notice alert exercises were conducted periodically to determine if bomber and tanker alert aircraft could meet the BMEWS reaction time of 18 minutes and 49 seconds set for the 306th BW in March 1964. Both "Bravo"(ready to taxi) and "Coco"(taxi to the active runway hold line) exercises were conducted. In March 1964 average "Bravo" times were four minutes for bombers and five minutes for tankers. Average "Coco" times were 12 minutes for bombers and 15 ½ minutes for tankers. Alert exercises were initiated by a klaxon and conducted no-notice day or night. When the klaxon sounded, aircrews did not know if it signaled an imminent nuclear strike or an alert exercise. Combat crew strength in March 1964 was 27 bomber crews and 29 tanker crews. The average work week for bomber crews was 70 hours and for tanker crews 73 hours.
In October 1963 the Wing prepared to support the SAC wide airborne alert program or "Chrome Dome." Under this program each SAC Bomb Wing was periodically tasked, for a specified period of time, to maintain a portion of its bombers airborne and ready to strike. On 16 November two of eight ground alert lines maintained by the 367th BS were converted to airborne alert lines. Two B-52s were flown in cell along the southern "Chrome Dome" route across Spain to the Mediterranean every day until 31 December 1963. Each B-52 required two air refuelings inbound to Spain and two more outbound over the Mediterranean. These missions were 25 to 27 hours long. The 306th ARS ground alert was also degraded to support "Chrome Dome" refueling along the southern route. The 306th BW was tasked to maintain airborne alert several more times until the Wing was deployed to support conventional bombing operations in Southeast Asia in 1966. Ground alert was reinstated at the SAC directed 50 percent of aircraft assigned rate after each "Chrome Dome" period. In January 1964, tanker crews changed to seven day alert tours while bomber crews maintained a three-four day cycle. One additional tanker alert line was added for a total of nine.
On 13 January 1964 the 306th BW entered into a no-notice "Bar None" exercise to test the Wings combat readiness. All crews and aircraft were flown in four days rather than the five days authorized. Air refueling support by the 306th ARS was rated "Excellent." The 367th BS was rated 98.8 percent reliable in bombs on target, with only two bombs scored unreliable. After the "Bar None" the Wing was rated second in Eighth AF on this exercise. A large banner stating, "We Clobbered The Bar None", was placed at the front gate of the base.
On 31 August 1964, Eighth Air Force tasked the 306th BW to train five crews in conventional bomb delivery. This tasking was in response to a SAC requirement to maintain a ready force for global flexible response. Each aircrew selected was required to accomplish two bomb drops on Matagorda Bomb Range, Texas. These training missions were code named "Iron Bomb" missions. This initial conventional bomb delivery training was later expanded to all 367th BS crews as SAC prepared to deploy B-52D wings to support combat operations in Vietnam.
On 16 November 1964 the 306th BW entered "Bar None" exercise "Sharp Needle India." After two days of low level bombing missions on "Fine Line Express" targets, the 367th BS had dropped seven unreliable bombs and failed the exercise. Six of the seven unreliable bombs were charged to crew error and resulted in the re-designation of three crews from "E" (lead crew) to "R" (combat ready).
On 27 November 1964, Colonel Earl L Johnson relieved Colonel Hand as Commander 306th Bomb Wing. The Wing continued to maintain eight bomber alert lines, and nine tanker alert lines. Modification of the B-52Ds to carry a total of 108 conventional bombs, "Big Belly", was started in December 1965. This modification increased the internal bomb bay load from 27 to 84 bombs, and added modified underwing bomb racks to carry 24 bombs, resulting in a maximum payload of 60,000 pounds of bombs. The paint scheme was changed from silver and white to camouflage and black. This paint change added 920 pounds to the aircraft Form "F."
B-52D crew training included conventional bombing tactics along with nuclear tactics. On 1 October 1965 a no-notice "Bar None" exercise was conducted to evaluate the Wings combat capability. The Wing failed this test. On 17 November through 20 November the Wings combat capability was evaluated during an "Operational Readiness Inspection Test" (ORIT). The Wing passed this test and Major General Creer, Commander, 823rd Air Division and Colonel Johnson recognized a B-52 crew commanded by Captain Robert Bruce as "outstanding crew of the ORIT."
During the period of 16 November through 31 December 1965, the Wing flew two B-52Ds a day supporting SACs airborne nuclear alert program, "Chrome Dome." The 306th BW flew the Southern route over Spain into the Mediterranean from McCoy and returning after a 25 to 27 hour flight. A total of 86 sorties were flown with an effectiveness rate of 100 percent.