What rarity would you give to this..? (5e)

[Sindal]

Hi all.

So I made a bow that's magic ability is its ability to cast counterspell once per day (by firing a arrow that counter acts it)

-Attunement required. While attuned, someone will be able to recognise when a spell is being cast as long as component is necessary.
-Arrows fired from the bow are considered magical
-The range of the counterspell is instead the range of the bow (max 600ft) . Disadvantage applies to the ability save roll if its fired from the longer range bracket and assumes a spellcasting ability of +3
-assumes a lvl3 cast of counterspell (possibly able to cast at higher levels if it absorbs enough magic over time)

What would you give this things rarity?

Also:

What rarity would give to a crossbow that has a permanent bless spell cast on it (holy crossbow)

[nickl_2000]

Counterspelling Bow - I'm bouncing between rare and uncommon, although if I were forced to make a decision I would likely put it as uncommon due to attunement.

Bless Crossbow - Constant +1d4 to hit and +1d4 to saves for a PC? As well as magical damage on a bow, I would put this into the rare range (although I could see it as very rare). It's got a better to hit than a +2 weapon and a better bonus to saves than a Ring of Protection. It is requires attunement, I would like fall into the rare camp. If it doesn't very rare.