As the Brewster B-339 aircraft used by the ML-KNIL were lighter than the modified B-339E Brewster Mark Is used by British, Australian, and New Zealand air forces, they were able to successfully engage the Japanese Army Nakajima Ki-43 "Oscar", although both the "Oscar" and the Japanese Navy's A6M Zero still out-climbed the B-339 at combat altitudes (the Zero was faster as well). After the first few engagements, the Dutch halved the fuel and ammo load in the wing, which allowed their Buffalos (and their Hurricanes) to stay with the Oscars in turns. In February 1942 they received new model gunsights. Around the same time the Dutch started to use tracer ammunition as well. These two improved their hit ratio. Still, their lack of heavy machine guns (.50") meant their success rate wasn't as high as it could have been.