Cowboys & Aliens (2011). So I just watched this tonight and thought it was pretty good. Not something that really breaks any new ground or has any life-changing message, just a good flick. So if you haven't seen it yet, I'll try to avoid any spoilers.
It's a mix, or mash-up, or whatever they call it these days, of two genres: western and sci-fi. There are several familiar western tropes that will give it the feel of many other westerns you've seen: an outlaw trying to go good, an evil cattle baron and his family of bullies who dominate a poverty-stricken town, a meek bartender (who, in this case, is also the town's doctor), a washed-out gold mine, etc.
It turns out that there also extra-terrestrials in the area, and they aren't the friendly kind. They're the kind that kill anyone and destroy anything that gets in their way, pretty much like the aliens from "Independence Day." So there's a collision of realities between the extremely advanced aliens and humans from 1873 who have a hard time wrapping their heads around what the aliens really are.
It gets a little too feel-goody toward the end for my taste, but I guess you can't have everything. I still say it's worth spending two hours on.
As for the guns. I never heard anyone say the specific year during the movie; the best I could guess was that it was in the late 1860s or early 1870s, not long after the Civil War. According to the official movie information, it was set in 1873. Almost all the handguns I saw were cap-and-ball revolvers (a wide variety and I am not skilled enough to identify them all), which would be appropriate for this time period--the Colt Peacemaker (the stereotypical western movie handgun) didn't actually begin production until 1873, so it would be unlikely that anyone in this isolated frontier town would have one. I did notice one Schofield revolver (which used a cartridge), which began production in 1870 and therefore is not an unreasonable handgun for 1873. Long guns appeared to be mostly Henry rifles and maybe a few early Winchesters--nothing that was out of place (or rather, out of time). The only specifically named firearm in the movie, which I recognized as correct, was the Spencer .56. The Spencer (in case you don't know) was a cartridge-fed repeating rifle that began production in 1860 and there should have still been plenty to go around by 1873. So, to the best of my knowledge, all the guns were correct! One thing I especially liked was that the Spencer was the only gun they had that was capable of dropping an alien with a single shot--as long as it was a head shot. The Spencer fired a very heavy 350-grain bullet, which to the best of my knowledge had a muzzle energy of almost twice any of the other rifles they had (which would have all been .44s of different sorts), and vastly more energy than any of the revolvers. So the effectiveness of the Spencer made a lot of sense, in my opinion.
Some people always have something to say about the casting, but that's not something really ever interests me very much. I was surprised to learn that the star was the same guy who's played the latest James Bond, and I think he played a very good western movie tough guy. There's even an obligatory Carradine (Keith). I must say that I am not looking forward to the day when a western movie is being made and there are no Carradines left to put in it. Oh yeah, Harrison Ford is in it. He played the cattle baron. I think this is the first time I've seen him play a total bastard* and he was pretty good at it.**
So, in conclusion, if you haven't seen it, check it out.
*Saying anything more about his character would be a spoiler, so that's all you get.
** Has Harrison Ford made any other westerns besides this and The Frisco Kid?