- "Six men came to kill me one time. And the best of 'em carried this. It's a Callahan full-bore auto-lock. Customized trigger, double cartridge thorough gauge. It is my very favorite gun… This is the best gun made by man. It has extreme sentimental value… I call it Vera."
- ―Jayne Cobb
The Callahan Full-bore Auto-lock was a weapon with armor-piercing capabilities. Jayne Cobb owned one of these weapons and named it "Vera". It was reputed to be Jayne's favorite gun, though it is rarely seen and it is not one of the weapons he takes to defend himself at the end of Serenity, instead preferring to use his assault rifle Lux against the Reavers. This is possibly because a higher fire rate would have been more useful than armor piercing rounds in that situation.
Although not obvious, its name seemed to indicate that the weapon can dynamically switch bore sizes depending on the cartridge size that the user desires. The weapon required oxygen around it to operate.
Behind the scenes
The "Callahan Full-bore Auto-lock" prop also appeared in the movie Showtime (2002) with Eddie Murphy and Robert De Niro, and is modeled with (mostly) bolt-on parts on top of a Russian Saiga-12 Kalashnikov-pattern semi-automatic shotgun. In the Russian language, the word "Vera" (вера - рус.) translates as: faith, trust, belief, and means serious hope. Also, it is a woman's name Vera (Вера - рус.).
The gun's apparent manufacturer is likely a reference to the "Dirty Harry" series, named after Clint Eastwood's character, "Dirty" Harry Callahan.