By any standard, the $105 million four-day box office haul for American Sniper is an astounding number. In just four days, it has gone from the Best Picture nominee with the lowest box office total to the biggest earner in the list of eight. (It had been in limited release in New York, Los Angeles, and Dallas since Christmas Day. It went wide this weekend.)

January movies aren't supposed to gross this much. R-rated movies aren't supposed to gross this much, as a general rule. And movies that aren't part of giant franchises aren't supposed to gross this much either. Why, just a few years ago, making a film about the Iraq War was considered a quick trip to box office disaster.

But there's American Sniper, giving a lie to all of this conventional wisdom. It's a tribute to the growing star power of Bradley Cooper, the terrific marketing department at Warner Bros. (which came up with a crackerjack trailer), and the fact that adult moviegoers will still turn out if they feel they have something to see. (See also: the impressive run of Gone Girl.)

But it's also a tribute to the eternal star power of Clint Eastwood, who isn't even in the film but is one of a handful of directors whose name carries enough weight to get moviegoers to check out his films. This doesn't always work — after all, he released the huge flop Jersey Boys just six months ago — but when Eastwood is matched up with a traditionally hyper-masculine genre (like, say, a war movie), he can attract viewers.

American Sniper is the best opening for a movie directed by or starring Eastwood, and if it has typical box office performance, it should get to $250 million. That would be the highest grossing Eastwood-related movie, unadjusted for inflation. But adjusted for inflation (i.e., making the ticket prices of yesteryear equal the ticket prices of today), it would only land at number two.

Eastwood's biggest hit? As Forbes's Scott Mendelson first pointed out, it's Every Which Way But Loose, the buddy comedy in which Eastwood plays a trucker who hangs out with an orangutan. If you put the $85 million that made in 1978 in 2015 dollars, the film would pull in $294 million. In fact, adjusted for inflation, it is still one of the 200 highest-grossing movies of all time.

Eastwood's second biggest hit when adjusted for inflation is actually Any Which Way You Can, that film's 1980 sequel, which made nearly $71 million then. That would be over $212 million now. Notably, Eastwood directed neither film, with James Fargo doing the honors on the first film and Buddy Van Horn on the second.

Thanks to January being a traditional dumping ground for new movies, there will be very little serious competition for the film in the weeks to come. That means American Sniper could very well pass $300 million and become the highest-grossing Eastwood-related film in history, even when adjusted for inflation, as Awardswatch's Jonathan Boehle points out.

But one thing is clear: Eastwood needs to reunite with his orangutan costar and complete the Every Which Way trilogy. The time is right.