As I said on the Regensburg Schweinfurt mission Spitfires handed over to P47s which turned back over Eupen in Belgium. from wiki
The Schweinfurt task forces followed the same route as the Regensburg force. Because of the delayed start of the mission, eight squadrons of
RAF Spitfire fighters (96 aircraft) from
11 Group and
83 Group had been added to escort the Schweinfurt force as far as
Antwerp, where P-47s would take over and escort it to Eupen.[
citation needed] The field order for the mission specified that the B-17s would fly at altitudes between 23,000 and 26,500 feet (7,000-8,000 m), but approaching the coast of the Netherlands at 13:30, it was confronted with developing cloud masses not present earlier in the day.[
citation needed] The commander of the first task force estimated that the bombers would not be able to climb over the clouds and elected to fly under them at 17,000 feet (5,000 m), increasing the vulnerability of the bombers to fighter attacks.[
citation needed]
. drgondog posted a typical mission profile years ago. Berlin required at least 4 possibly 5 waves from memory plus others to escort individual stragglers that had dropped out of formation. It wasn't a question of p-47s or p-38s or P51s they needed all of them and pilots too. This is why even when the P-51 was arriving they were still pushing to extend the range of others with internal and external fuel. There had to be massive safety margins built in. Sometimes the rendezvous was missed, sometimes the pilots were in combat longer than 15 minutes, sometimes the ground speed of the bombers going into a head wind was as low as 120MPH. The escorts had to stay with the bombers no matter what and that meant huge "contingency", despite this, reports of pilots landing exhausted with little more than fumes in the tank are common. I believe everyone here has been extremely cordial, but if you hadn't considered that the escorts operated in waves then maybe you could consider that it is a more complex issue than you thought. It is certainly not an issue of whether a plane could reach Berlin or not.