Siege Rifle (5e Equipment)
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Martial Ranged Weapons
An attempt at taking light and heavy machine guns, and rebalancing / reflavoring them to work in standard campaigns, as part of an ongoing 'fantasy firearms' project.
Simple Trigger If the wielder is capable of wielding oversized weapons, they can treat light siege rifles as if they had the Versatile property. When wielded in one hand in this way, the damage is reduced to 2d6. Two or more hands must still be free in order to reload.
Tripod (15gp, 1 lb.) Siege rifles with a tripod are designed to be fired from a prone position. When willingly dropping prone, you may choose to prop this weapon onto its tripod. If you are prone and the weapon is not propped up (i.e, you were knocked prone by an enemy), you may prop it up as a bonus action. When wielding this weapon while it is propped up on its tripod, you ignore the heavy property, and do not have disadvantage from being prone. However, while this weapon is already hard to hit a foe in close range with, firing at an enemy in melee range in this position is outright impossible.
Ammunition: Unlike similar era firearms, specialized magazines were crafted to hold the weaponry. Each magazine holds enough to make six attacks with this weapon before reloading, but each trigger squeeze fires multiple bullets. Reloading this weapon without using the entire magazine is potentially wasteful, as once assembled, the magazine cannot be taken apart without specialized tools. Transferring ammunition from one magazine to another is extremely difficult. Magazines cost 2 gp each.
Heavy Siege Rifle
The original siege rifles were designed to be oversized even for their small-sized creators. As such, the oversized variant of this weapon (a "heavy siege rifle") is not uncommon. It costs 500 gp (530 with a tripod), it's damage is improved to 2d8, but attacks with it are made at disadvantage unless the wielder is large size, capable of wielding oversized weapons as if they were large, or using the weapon's tripod. A "doubly-oversized" version also exists, difficult to wield even for creatures with a mighty frame. It costs 1090 gp (as they always have a tripod), and its damage is improved to 2d10, but even large sized creatures must use its tripod to fire it effectively.
Siege Rifle Fortification Treading the line of what we can pretend isn't anachronistic even further, some gnomes have "reclaimed" the concept of building very large siege rifles, but replace the tripod with a much heavier, easier to wield setup. Some of these variants can take a full minute to pack up or unpack, while others are permanently affixed to the ground or the top of an armored wagon. The largest versions in the latter category inflict 4d8 damage. In all cases, they cannot be wielded normally, but when setup as a fortification, can be effectively wielded by creatures of any size. It's believed these new advances will revolutionize war, but they are so recent and require such fine craftsmanship that they haven't caught on yet, outside of a very localized area.
What is now considered the Light Siege Rifle was originally a work of gnomish craft, invented in fairly recent years. The prototype Siege Rifle was an expansion of the already masterwork riflecrafting gnomes were capable of. It features rotating barrels, a bottom-fed magazine of ammunition, individually proportioned explosive charges for firing, and a hand-crank operated tripod so gnomes (with their small bodies) could fire from a prone position and not have to worry about the recoil. The inventor, Natibi Griesha, was reportedly as charismatic and confident as she was brilliant. Even then, she invented it as a novelty; an advertisement for the inventor's family brand, that drew investors, mercenaries, and even war suppliers from across the country to witness it and make purchases. At the time, the sheer number of complex, delicate parts, expensive materials, lack of efficiency per bullet compared to mundane rifles, and haphazard assortment of necessary extensions (such as coolant, stability braces, weights for balance, and magic enchantments to its durability) left it a hugely expensive, high effort undertaking that made it impossible to mass produce.
But, with the Greisha family name's pre-existing fame and fortune exploding beyond their expectations, the design was revisited. Lessons from building the prototype were applied, and adjustments to the frame were made. The design was refined again and again, until it no longer even needed magical enchantments to function. The result was the first model of Siege Rifle capable of larger scale production. Granted, the cost of production was still very high, but it became a staple for the armies of the surrounding area to train small groups soldiers in this weapon's use. Its price wasn't much of a hinderance, its nature made it effective as a "specialist" weapon, highly effective in the right situations, while being overly specialized in others.
As it spread, knock-off brand siege rifles gained prominence. They were cheaper, but less effective. Industrious humans and dwarves started by taking advantage of their own size, ignoring the need for a stability tripod, then later made larger variants. Although it always remained an exotic weapon, it stopped being synonymous with the Greisha brand, and the family lost some of its fame. The smaller variety of siege rifles were eventually considered "light" siege rifles, as if to imply they were not the default.