Campa (Carlos Gallardo) shows up to the firefight with a pair of guitar case machine guns. Robert Rodriguez has commented that the guitar case machine guns were built from MAC-10s.
Based on the sound effects made by the guitar cases, I'm pretty sure they were supposed to be miniguns concealed in there, even if they used MAC-10s as the firing portion of the prop. Hexslinger 16:06, 22 September 2009 (UTC)
Ponytailed ganster uses a Beretta 92FS Inox pistol with Ivory grips to hold up El Mariachi in the bar. Some random thugs can be seen using them as well.
El Mariachi (Antonio Banderas) carries a scoped Wildey Magnum pistol in his guitar case. One of Bucho's hitmen is also seen carrying a Wildey Magnum in the film.
El Mariachi (Antonio Banderas) can also be seen using a Rossi Overland Sawed Off Double Barreled Shotgun as one of his main weapons in the film and can be seen firing up to six rounds from two barrels thanks to movie magic. It was built and supplied by Stembridge Gun Rentals
In the shootout at the Oro verde bar in Saragosa, El Mariachi pulls out a Sentinel Arms Stryker 12, along with the sawed off 12 gauge, that Buscemi described as "The biggest hand cannon I've ever fucking seen." El Mariachi used it to send several thugs flying (unrealistically) but sadly, it is the only time he uses it. A thug later in the film is seen using it, but very briefly.
Tavo (Tito Larriva) fires a black Desert Eagle in .50 AE caliber (determined by bore diameter) at El Mariachi (Antonio Banderas) as he flees the shootout at the Tarasco bar. Bucho (Joaquim de Almeida) also begins to kill his own men with the same black Desert Eagle. El Mariachi (Antonio Banderas) later kills one of Bucho's henchmen on the roof of Carolina's (Salma Hayek) bookstore who is holding the same black Desert Eagle.
Bucho (Joaquim de Almeida) seems to have a taste for exotic pistols, the Beretta 93R he carries is a very rare version of Beretta's popular 92FS model capable of 3-round burst fire. Bucho (Joaquim de Almeida) Beretta 93R is taken by Zamira (Angel Aviles) who makes use of its burst fire capability in the attack on Navajas (Danny Trejo). The Beretta 93R is later reused by one of Bucho's henchmen who fires at El Mariachi as he jumps from the roof of Carolina's (Salma Hayek) book store.
Although we never see the Codpiece Revolver fire it's one of the few firearms in the film with dialogue devoted to it. This same codpiece revolver was later reused by Robert Rodriguez in From Dusk Till Dawn. Originally a scene was shot where El Mariachi used the codpiece, which was hidden under his pants, to shoot Ponytail thug, before whipping out his Ruger P90s and finishing him.
The Tarasco bartender (Cheech Marin) uses a suppressed Smith & Wesson Model 19 revolver. In reality, very few revolvers can be sound suppressed because of the gap between the cylinder and barrel. The 1895 Russian Nagant revolver is one of the rare revolvers that can be sound suppressed. Upon firing, the cylinder moves forward and seal with the barrel, leaving no gap. You can see it here.
It is also possible that this could be a bit of creative license on the part of the film makers, as the US military attempted their own version of the nagant to be used by tunnel rats, it was based on a smith and wesson model 29 (which looks very similar to the 19), it never entered service, but it is possible that this is what the armourers were aiming for
Most of Bucho's (Joaquim de Almeida) men are armed with suppressed MAC-10 machine pistols that are most prominently featured in the Tarasco bar shootout, some with mock suppressors, some without. You will recognize the scene between El Mariachi (Antonio Banderas) and Empty Gun Man (Diego Sandoval) as inspiration for a similar scene between Agent Smith (Hugo Weaving) and Neo (Keanu Reeves) in The Matrix.
Empty Gun Man (Diego Sandoval) brings a suppressed Taurus PT99 to the Tarasco bar shootout. El Mariachi is later seen with the same PT92 in his guitar case later, although it lacks the suppressor. It is noted as a Taurus PT99 based on its frame mounted safety and raised adjustable sights.
Some thugs in the film use a Remington 870 with a sawed-down pistol grip, extended magazine tube, and a heat-shield similair to the gun used by Denzel Washington in Training Day.
El Mariachi takes two M26 hand grenades from his guitar case on the rooftop, pulls the pins with his teeth (despite the 5lb pin pull) and then throws them at the two men on the street below. The grenades make a ridiculously large fireball instead of a more realistic explosion.
