1109 GMT April 20, 2019
"Raptor reached 268.9 bar today [approximately 274.2 kilograms of power per square centimeter], exceeding prior record held by the awesome Russian RD-180," Musk said on Twitter, according to sputniknews.com.
On February 4, Musk said that SpaceX had conducted the first test firing of Raptor.
Russian liquid-fuel rocket engine RD-180 is used in the first stage of the US Atlas-5 rocket. According to Russian rocket engine manufacturer Energomash, the pressure in the combustion chamber of the RD-180 is 261.7 kilograms of power per square centimeter.
On January 31, Musk posted a couple of images on Twitter showing a Starship Raptor engine and saying SpaceX was preparing to test fire it at its Texas facility.
So far, SpaceX has completed the assembly of a stainless Starship Hopper prototype meant for takeoff and landing tests.