QQ--Irresponsible Turn Push?

[feelixthegreek]

1/2 NL at my local B&M:

Sit down and give $200 to chip runner. On my immediate right the big stack has a little under $500. I'm BB in first hand and owe the table a time drop. I fold, and after the hand the big stack pushes me a stack of reds to use while chip runner gets my chips. I count out the stack and it's $10 light. I mention this and he gives me the missing $10. I don't believe he was intentionally trying to take me for $10, but I wonder about players who a) loan out their chips to a new buy-in, and b) get the count wrong. Surely there's a read to be found in that behavior.

I fold my small blind hand, get my acutal chips, then pick up QQ on button. Three people limp for 2, including big stack (game is 6 handed and there's not much $$ on the table overall). I make it $20 to go, expecting loose calls, as is the norm from a couple of the players I've sat with before. Instead everyone folds to big stack, who calls takes the flop heads up with me.

Flop is 987r. Checked to me and I bet $40 and am called. I plan to check any turn card that makes the board worse, but a blank comes and I'm checked to again.

I'm wary of pushing (my stack was = to the pot size), but I did anyway.

Since reading NLHETP, I've been conscious of trying not to overcommit myself with overpair and top-pair hands, but is my push standard here, or am I overrating my oppenent's potential for loose play?

[Ben86]

id check behind here. whats he going to call you with that youre beating? your action says overpair and hes a limp/called/called. if the river blanks id call or put in a value bet (if this is your stack then fine) but id have to fold to a J-6-10 possibly an ace as well.