I'm not sure about the definition of spaghetti western, but I know that 100 Rifles was filmed in Spain and has a lot of violent action in it.
Burt Reynolds is Yaqui Joe, whose mother was a Yaqui and whose father was from Alabama (which explains his accent). He's stolen $6000 from a bank in Arizona to buy rifles for the Yaquis.
Raquel Welch is Sarita, the beautiful revolutionary who's to receive the rifles.
Jim Brown is Lydecker, the lawman who's chased Yaqui Joe into Mexico and is intent on bringing him and the money back.
Fernando Lamas is General Verdugo, who's intent on wiping out the Yaquis.
Eric Braeden is the German "adviser," and Dan O'Herlihy is the representative of the railroad that Vergugo needs.
I don't need to tell you anything about the plot. Just watch the trailer below. It tells you the whole movie in under 3 minutes, although it does leave out a few things, including the one thing that surprised me. At the time of its release, the movie created a bit of a sensation because of the love scenes between Welch and Brown. I don't think Welch's shower scene bothered anybody. It's in the trailer.
Reynolds is pretty good as Yaqui Joe. This was before his days of stardom. Brown isn't a great actor, but he has presence. So does Welch. Fernando Lamas is a hoot, and O'Herlihy is very good. There's plenty of action, lots of explosions, and some nice scenery. Jerry Goldsmith's score is good, too.