I'm new to air guns, what's classed as long distance?

I was at the Greyhound last week (Nr Coventry) and I managed to hit a few of the targets on their plinking range at 60 yards, not too many times but its difficult to see where you're missing at that distance.

Gun is a Pro Sport .177 with Air Arms Field. It's fairly new having only one tin through it. Scope is a Hawke Map Pro 3-9x50

I zeroed it at 30 and used each dot as a 10 yard increment and it seemed to work pretty well although I'm hoping I'll get better with practice as I'm still getting used to just about everything.