In spring 350, Murong Jun launched the attack, and they quickly captured the important city of Jicheng (薊城, in modern Beijing).
Murong Jun then moved the capital from Longcheng (龍城, in modern Jinzhou, Liaoning) to Jicheng.
In short order, the entire Youzhou (幽州, modern Beijing, Tianjin, and northern Hebei) became Former Yan possession.
He then continued to march south, but temporarily halted his advances after nearly being defeated by the Later Zhao general Lubo Zao (鹿勃早).
Murong Jun sent his general Yue Wan to join Shi Zhi and his general Yao Xiang, and their joint forces dealt Ran Min a major defeat, forcing Ran Min to give up on sieging Xiangguo for the time being, although soon thereafter Ran Min was able to persuade Shi Zhi's general Liu Xian (劉顯) to kill Shi Zhi, ending Later Zhao.
During the heat of the battle, Ran Min's horse was killed; he fell and the Murong troops captured him.
When Ran was taken to Murong Jun, the latter famously rebuked him: "How could a lowly knave like you have the audacity to be a Pretender to the Throne?"
(汝奴仆下才，何得妄称帝) However Ran Min, an ethnic Han, accused Murong Jun of being "an over-ambitious barbarian Pretender" in turn.
In 355, angered that his cousin Duan Kan (段龕), who was in control of modern Shandong and nominally a Jin vassal (as Duke of Qi), wrote a letter to him denouncing him for claiming imperial title, Murong Jun sent Murong Ke and Yang Wu against him.
In 358, Murong Jun started a large scale conscription—ordering that each family send its service-eligible men into the army except for one per household—preparing to attack Former Qin and Jin.
After a petition by Liu Gui (劉貴), he scaled back the conscription plan, ordering that for every five service-eligible men of the household, three enter the army.
Murong Chui was effectively exiled to be the governor of remote Ping Province (平州, modern eastern Liaoning).