|“||Spitfire’s Thunder, is a magically enhanced anti-machine gun. Made fer a pegasus sniper. It’s enchanted so’s to weigh only a few pounds an’ t’ have only a feather-brush of a kick. Fires more like a magical-energy weapon than a firearm. Even has a lightnin’ gem fuelin’ her insides -- that’s why she sounds like thunder when she’s shot. She fires probably twenty percent faster than the non-magical model and won’t never jam. No moving parts. Alla which means she’s more magical energy rifle than firearm. But she still uses bullets, just like muh battle saddle. An’ bullets are subject t’ wind and gravity. So that makes for an odd combination. An’ that means Ah best get some love in with her on the firin’ range before takin’ her inta battle proper.||”|
– -Calamity describing the mechanics of Spitfire's Thunder to his companions and the Steel Rangers
The Rifle is in pristine condition having been kept safely in a bank vault for the last 200 years. The rifle has flame-styled filigree, a custom bit, deep citrines imbedded in the barrel and an embossed nameplate that reads Spitfire's Thunder. It was found broken down to fit in its container along with a few Memory Orbs.
Not much is known about the weapons origins. It is named after the famous Wonderbolt Spitfire. It is a powerful, unique variant of the anti-machine gun rifles, with built in gems/talismans that absorbed the recoil of the massive weapon. This would allow a pegasus to use the weapon and not get knocked off course by the recoil.
The rifle was given to Calamity by Littlepip, since he showed so much knowledge and enthusiasm regarding the weapon. The Steel Rangers tried to confiscate it from Calamity and opened fire upon him. They were deterred from this course of action as Steelhooves was in Littlepip's group and outranked the Rangers in question, since he was a Star Paladin.
In the Shaping Shadow Series, Spitfire's Thunder is given an origin story. It is created by the genius gunsmith and firearm designer Walter. Walter not only owns and operates Walter Arms, but also created many of the weapons found in the wasteland. Both military and civilian weapons.
Spitfire's Thunder, and its sister rifle Soarin's Lightning, were hoof built by Walter for their respective pegasi. The gemstones were enchanted by Trixie Lulamoon. Walter only ordered the gems and their enchantments, the choice for Trixie to enchant them was made by an unknown pony.The rifles never got delivered and due to security concerns, they were stored in the Bank of Equestria until the presentation date. Shadow Flare raided the bank vault, but he only had time to recover Soarin's Lightning. The bank vault was sealed up and the automated defenses were brought back online at full strength.