I dont actually know whether its a bug or a intended nerf but after update I detected some differences in accuracy/performance of M4A1. When I tapfire very fast without moving at a single target then after the first few bullets the gun starts to loose accuracy completly and the bullets spread widely all around the target. When I tapfire very slow then nothing like this happens, every bullet is quite accurate then. But this just happens with M4, other guns seem to work the same way as before. If its necessary I can also try to record this.