$1-$2 private game, very soft. Villain is well-known to hero: Guy in his 60s who gambles it up and plays splashy when he's winning. He rarely leaves a winner. Has recently run his stack up to $600. Stacks are $500 effective.

Hero has 66 in the big blind. One limper from MP. V overlimps from LJ. CO raises to $12, BTN calls, H calls, V calls.

Flop ($47) is 567

H checks, V donks $45, folds to H.

Given the pot-sized donk bet and stack sizes, I decided to put V on a range of hands he wanted to protect, as opposed to some sort of big draw where he'd rather check to the raiser. So I'm thinking: A7, K7s, 88-TT, 75, 55, 34. Flopped nut straight like 89 is also possible, protecting versus the flush draw, but I think this guy tries to get trappy with the 89. He also tries to trap with a hand like 77, so I'm taking that out of his range as well.

So in deciding that he had a hand that he wanted to protect, and given that I'm ahead of most of his range here, I elected to min raise to build up the pot and keep him in the hand. So I make it $90. Villain thinks for about 5 seconds, then calls.

Turn ($137) is a blank: 2

I lead for $100. Now V raises to $300. Pot is $537 and it's $200 to call. If I call, I'm committed and putting the last of my chips ($110ish) on the river. The 1 pair hands are probably no longer in his range.

What's the best play here?

Fill up otr

Fold. You only beat 55.

I think you're getting close to the right price to make calling correct. If he has a straight or 77, he played it very poorly so there is some chance our hand is good. Also, lead flop.

If V is as you described him (likes to gamble, splashy) I think he's wider than you give him credit for and I'm never folding middle set here. The turn bricked and we're building the pot to play for stacks, so let's do it - ship it ott before he can hero fold his draws when they brick.

Also, if your range for him is correct otf, you're only losing to 43. Considering he's spewy, wide, and loose, (and we have 10 outs to fill / quad up) doing anything other than getting all your money in the middle is criminal.

As4s As6s As8s all should be in his shove range here too. Like DormantDhark said, get it in before his draw misses.

If he wins, you play with him on a regular basis so it's good to let him be happy sometimes in the long run you will get him back.

Edit: 4s6s 6s8s should also be in his shove range

Yeah, you are committed if you call, so I'd basically think of this as 650 in the pot and 310 to call (rather than 540 in pot and 200 to call), just to make it simpler.

So it seems like we are looking at something like:
14 hands you beat (55, 75, 65, 76)
19 hands you lose to (77, 43)
plus you probably have the full 13 outs against 43

So it looks like a pretty easy call to me. Even if you allow for 98 I think a call is still fine (tho it's much more borderline obv but I'm too lazy to do the math right now).

I elected to shove and this is what most closely matched my rationale at the time. I talked the hand over with a friend who plays higher stakes and he thought this was a shove as well.

I just always hesitate sometimes at $1-$2 when I see aggression and absolute sizing like this. Pot odds aside, it's very often that V's have the nuts or near nuts in these circumstances. The question was whether this V was making his move with a worse set or a better hand like 77 or one of the straights. A sick draw like Ax was possible, but I did discount that based on the way this V played the flop. I assigned a very low probability of a bluff.

FWIW: Villain had 34 for a low-ender. So he was protecting as I surmised, just protecting one of the hands that was better than mine. I failed to draw to my outs and lost the hand.

Thanks for the comments, all.

Villian built his stack up to a nice $1300, then promptly lost it all within about 2 hours!