Bound Weapon

You summon into existence, for 1 hour, an ethereal form of a weapon from the table in the PHB pg.149, the weapon is of your choosing and are considered proficient with it. The conjured weapon functions as it's normal counterpart except that it is weightless, considered to have the "Finesse" property and creates it's own ammunition if it's normal form uses it. If a weapon conjured in this manner requires ammunition,  the ammunition will be created when the weapon is used in the manner in which the ammunition is required(IE: bow string is drawn, crossbow is cocked, sling is slung). 

At 5th level, the weapon you conjure becomes more powerful and gains some new properties. The weapon is now considered to be a +1 magical weapon. During a short rest you may choose to attune yourself to the weapon. If you do so, the weapon will remain in existence until you dispel it or you fall unconscious.

At 9th level, the weapon you conjure is a +2 weapon and you cannot be disarmed of it by any means.

At 13th level, the conjured weapon is now a +3 weapon and is able to directly effect creatures in the border ethereal as normal.

At 17th level, the conjured weapon is a +4 weapon and is now able to have a secondary energy type associated with it upon summoning. This secondary energy deals 2d6 points of damage on a successful melee strike in addition to normal weapon damage and any other damage the strike deals.

At 20th level, the conjured weapon is a +5 weapon and has reached the apex of it's power. In addition to all previous abilities gained it now possesses the ability to bypass all armor.

The secondary abilities gained on the 9th, 13th, 17th, and 20th levels are depended upon the attunement of the weapon. If no attunement is made, the weapon will still gain it's magical bonus on those levels when conjured.