I saw this in another poem long ago and now again, in The Bell Tolls for No One. I don't gamble or go to the horses, and googling it didn't give me a precise definition. Does anyone know what this means exactly, in the world of gambling?
I don't know this for certain (and I don't recall the context from that book) but my sense it that it refers to going against what the general public views as the best bet. Buk wrote about this a few times: the general public looks at the form and a longshot's performance in past races and throws their money away on the 20:1 longshot - the sucker bet. So "bucking the take" would be avoiding the choice of the general public and choosing a better horse (considering the odds, is the horse a front-runner or a closer; all those things that he claimed at various times to have in his "system").
The one I have on hand, from The Bell Tolls for No One, it's true provenance is actually "Notes of a Dirty Old Man," L.A. Free Press, April 20, 1973. In it he writes:
You might say that if you bet $2 nine times with a fifteen percent take, that you are bucking a take of nine times 15 percent, which on that theory is bucking a 135% take, which might explain why most people leave all they brought with them at the track.
I hate math and I really just thought it was a common gambling term (it isn't, at least anymore), so I assumed it would be easily deduced. It wasn't. Until you helped.
No, the take is what the track "takes" off the bets -- their cut, i.e., if you bet $2, the track gets 30 cents (15%) for itself and the rest ($1.70) goes back in the pool with everyone else's bets. So, that's why he says if you bet 9 times that's $2.70 you have to win just break-even, or 135% of $2... That's why most people lose.
There is an old term for betting against what the public thinks is the best bet -- "copper the public" -- see Roger Bacon's classic book Secrets of Professional Turf Betting. (Yes, I used to play the ponies now and then... but just for kicks. The only gambling I do now is occasional poker).