The maximum, 100% the best it can ever get, the biggest, the most etc.
"Go full-bore! Get 'er outta the mud!" Carl said to his buddy trying to drive through a huge mud puddle.
In other words, "Bring it all in"
When there is a full out. Full moon and empty legs.
"Hey dude. Do you have to go to this dance thing?"
"Negative. The tower is full."
When your friend is too high & can't form a sentence.
Ryan said "I have a rock full of pockets" as he sat in the creek playing with the sand & rocks.