Crescent Rose

Crescent Rose is Ruby's weapon of choice. It is a High Caliber Sniper-Scythe (HCSS) - a hybrid between a scythe and a sniper rifle. Ruby is first seen wielding it in the "Red" Trailer.

Description
As its name implies, Crescent Rose's frame is colored rose-red with black trims, with its large scythe blade forged into a crescent shape. Ruby's crest is engraved onto the circular swivel frame of the weapon.

The most notable property of Crescent Rose is its converting frame: it allows Crescent Rose to transform to different modes of combat, from a full-scale scythe and sniper rifle form to a condensed rifle form. It can also fold up tightly and be holstered for easy convenient transportation, stored underneath Ruby's cloak at her waist. Also, though it appears to be a bolt-action weapon, it does not need to be in its gun mode to fire.

In order to use Crescent Rose to its fullest potential, it is implied a scythe-wielder of equivalent skill to either Ruby or Qrow would be necessary. In particular, the user would have to deal with Crescent Rose's massive recoil: rather than compensate for it, Ruby uses the recoil to amplify her overall combat prowess. Ruby also uses the recoil to enhance her mobility in combat; firing shots to propel herself short distances, using it to simultaneously attack and evade.

She also uses her weapon's recoil to launch herself further higher in the air, as staying for a certain amount of time, such as seen after being launched by Weiss into the air when facing the Nevermore. In melee combat, Ruby can fire a shot immediately before a swing, using the recoil to accelerate the scythe to increase the force and speed of her attack. She can also embed the scythe's blade into the ground to prevent the weapon's recoil from changing her current position or stance.

It is possible that standard round magazines have a 30 round limit, as in the "Red" Trailer she reloads after 30 shots if counting the shots off-screen but heard the SFX for.

Construction
According to Professor Ozpin, Crescent Rose is described to be "one of the most dangerous weapons ever designed." In Episode 2, Ruby comments she was the one who designed Crescent Rose, although she also admitted she went overboard with its design.

Crescent Rose appears to be a highly advanced technological piece of equipment. Its collapsible frame allows it to transform between three different modes: In addition, because of the frame's light-weight design, it can freely shift from these three modes both smoothly and quickly. The drawback: because of its lack of substantial weight and its high-energy output, each shot fired from Crescent Rose carries a very high recoil. The weapon also requires large specialized ammunition with a limited round-per-magazine capacity.
 * a "storage" mode, its most compacted form, where it's condensed for travel convenience when not being used;
 * a "rifle" mode, where it takes the form of a medium-length bolt-action rifle, where the absence of the scythe makes for more effective use of the rifle part of the weapon; and
 * a "scythe" mode, its most expanded form, where it fully extends into the form of a scythe, allowing it to be used as a mid-to-close-range bladed melee weapon, that also doubles as a long-barrel sniper rifle for more precise, long-range, high-energy shots.

Trivia

 * The Scythe has a small, jagged blade at the bottom of the shaft, perhaps used for swirling attacks or a counter weight.
 * Ruby seems to have no difficulties with 'unsheathing' it or extending the scythe's blade, suggesting that Crescent Rose is mechanical and can operate itself.
 * Professor Ozpin notes that Crescent Rose is "one of the most dangerous weapons ever designed." However because Ruby claims to have designed it herself, Ozpin is most likely referring to scythes in general. Another explanation is he examined Crescent Rose himself, since it is not present on Ruby during her interrogation.
 * It is likely that Ruby partly named the weapon after herself, since it bears her last name. Crescent comes from the shape of the blade, the same as a crescent moon.
 * When the weapon fires it produces what appears to be rose petals, this could be where the other half of the weapon's name comes from.
 * Ruby at one point affectionately referred to the weapon as "Sweetheart," showing her fondness for the weapon.
 * Ruby's recoil use of her weapon is similar to how Nora uses her Magnhild, in which she also uses the recoil ability to propel herself certain distances or to add force to her strikes.
 * The weapon's original form was a Barrett M82 sniper rifle with minor changes, and with the scythe mounted at the end of the barrel. The final version has very little in common with the M82.