The motor has a diameter of 11.48 foot (3.5 meters)1 and a maximum thrust of 1,00,000 pounds-force (500 tons) is powered by 330,000 pounds (150 tons) of solid fuel.
Yeah it was made by the same department who manufactures China's ICBM. The engine you mentioned has a more detailed specification
in a journal written by former leader of the department, Tian Weiping, in 2020.
对于航天运载与助推领域,大型化是固体火箭发动机的发展目标。一方面,发展先进整体式大型固体火箭发动机,突破纤维壳体、大型柔性喷管等技术,实现发动机直径3.5 m、推力500 t、工作时间120 s、质量比≥0.93,为全固体运载火箭提供高性能基础级动力; 另一方面,发展大型金属壳体分段式固体火箭发动机,突破分段燃烧室对接、大流量高可靠矢量喷管等技术,实现发动机直径3.5 m、5段式、推力1500 t、工作时间120 s、质量比0.86,为重型运载火箭提供高可靠助推动力
"The Isp and mass ratio of solid rocket motors should achieve 305-310s
, respectively, to meet the demand for solid rocket motors in strategic fields.
In order to meet the performance level and adaptability demand of future tactical missiles for solid rocket motors,..., it should have its Isp and mass ratio to reach 265 s, 0.90.
For the field of space launch vehicle and booster, the development of advanced integral large solid rocket motors, breakthroughs in fiber shell, large flexible nozzle and other technologies to achieve engine diameter 3.5 m, thrust 500 t, working time of 120 s, mass ratio ≥ 0.93 and a solid motor of 3.5 m, 5-segment, thrust 1500 t, working time 120 s, mass ratio 0.86 for heavy launch vehicles."
The 500t motor has conducted its hot test in late 2021 and the strategic motor could have been tested already sometime between 2020 and 2021 but not made public for the obvious reason.
It is very impressive that if the motor has a vacuum Isp over 305s and mass ratio over 0.95, and if not mistaken it could be the most advanced solid motor ever made.