http://de.wikipedia.org/wiki/Fallschirmj%C3%A4gergewehr_42
That thing has a pudding scope, of course falls are deadly on long range. And you were outnumbered, 3 fallschirmjäger squads wipe 3 infantry squads like nothing, the AT-guns do nothing against Inf, and the 3 volks vs the AA HF?
How can you think you should have won? Serious question without trying to be offensive. 6 inf squads against 3 inf, 2 AT and 1 light vehicle...
