5/10 Party hand......standard?

[300CE24]

6-max, 6 players

Button ~$2500
BB ~$1000
Me ~$1000

Just sat down, all players unknown to me.

Preflop:

I look at 77 in the SB
Fold to Button, who calls
I make it $40
BB calls
Button calls

Flop 78Jr:

I bet $80
BB calls
Button makes it $250
I push.

Comments?