Corrected entry: When Riggs is pinned beneath the concrete slab, Murtaugh staggers to his feet. His coat opens, revealing an automatic pistol in a holster. He was always known as a wheel gun guy, so why the automatic? And, if he had it, why didn't he use it to kill the guy in the white pajamas?
Corrected entry: Not really a mistake, but perhaps worth a look. In the previous three movies Mel Gibson's character wore his watch on his right hand. In this one he wears his watch on his left.
Correction: Like the submitter says, not a mistake at all.
Corrected entry: In Lethal Weapon 1, Riggs' wife's grave has a very small stone in the ground, but in this one when he leaves his ring, it is a much larger tombstone.
Correction: Gravestones can be upgraded. In the 11 years between the two films, it's possible that Riggs decided to buy a bigger grave marker for his wife. (Particularly if he plans to be buried with her so that his name can be added later.).
Corrected entry: When Riggs and Murtaugh are talking about how much ammo they have, Murtaugh says he has 6. He then shoots 2 and say he has 4 left. Next time Riggs asks Murtaugh says he has 2 left. When Butters is shot, Murtaugh fires 2. So he should have 0 shots left. However he still has one more, because he shoots Wah Sing Ku's brother. So where did the 7th bullet come from?
Correction: Although difficult to see, in some shots Murtaugh is seen using his Smith & Wesson 5906 in addition to his Model 19. In one shot he's seen holding one of the Triad's Makarov PM's which he must've picked up (most notably scene when Butters gets wounded), so that explains why he seems to fire more than six shots.
I'm watching the movie right now. At 01:41:27, you can see he is using his revolver for the "extra" round. IMFDB doesn't even have Murtaugh using the S&W 5906 during the final shootout nor the Makarov, which it looks like he does not pick up until after this scene. The original post is correct.
Correction: Remember that they had to find new guns because they ran out of ammo during the shootout. He just put away the one that still had ammo.
LorgSkyegon