well whats the prob then mate?

if your sparring guys a lot bigger, then you are gonna struggle to land your shots, but its all good training, if you can break down a bigger guy, like you said when your with people of your own size you are landing fine!

Whats your record like?

also its not surprising your not getting through a bigger guys defence, he can soak up more of your shots, and the danger of a counter is magnified, so you will be to an extent 'glove shy'