After several weeks the weather improved and 301 Squadron rejoined the bombing campaign over France and Germany. Targets struck included, among others, Bremen, Hamburg, Cologne, Brest and Essen. On 17 April 1941 three crews took part in bombing of Berlin for the first time. On 18 July 1941 the two Polish bomber squadrons were moved to RAF Hemswell. In 1941 the squadron's aircraft undertook 436 missions, with a loss of 9 crews. On 12 February 1942 the squadron took part in an exceptional daylight operation against Channel Dash of German battleships, but did not find targets due to bad weather. On 28 March 1942, during a raid against Lübeck, one crew shot down Junkers Ju 88 night fighter. On the night of 30/31 May 1942, fourteen aircraft took part in a thousand-bomber raid against Cologne (Operation "Millennium"), without losses. This was Arthur Harris' first large formation raid. On the night of 2/3 June the squadron took part in the second thousand-bomber raid on Essen, losing one crew, but in another smaller scale Essen raid on 5/6 June two crews were lost. On 25/26 June fourteen crews bombed Bremen in last thousand-aircraft raid, losing a crew of the squadron commander Stanisław Krzystyniak (taken prisoners). On 2/3 July yet another two crews were lost over Bremen, with the new squadron commander Maj. Maksymilian Brzozowski, who was taken prisoner as well. Over the night of 21/22 July, another two crews were lost to enemy flak and night fighters over Duisburg. In total, six crews were lost in June and five in July 1942, making these months the worst in the squadron's history.