Confidence is key and if you have doubt in your mind over some piece of your kit or even yourself it can put you in this position,its on your mind and goes round and round and I suppose becomes a sub conscious off put,get out and practise Mac and get that belief back,you know the feeling that everything is spot on at different ranges,magnification etc,I'm sure you do this often enough anyway but there's no harm in doing it once more,if you find you don't get on with .177 after then a trade in is understandable,may as well have a gun you can confidently grab and go...