Sayyed Mohammad Al-Musawi, Sayyed Mohammad al-Musawi is originally from Iraq and heads up the World Ahlul Bayt Islamic League in London. Other than being involved in various humanitarian projects, he frequently responds to... Answered 2 months ago

There is no book of Hadeeth compiled by Shia or Sunni scholars which is 100% and fully authentic in each and every narration. Al-Kafi is the most authentic book of Hadeeth among Shia scholars. Bukhari is claimed to be fully authentic by many Sunnis but it contains narrations which go against Quran and allegation against the Prophets. The authentic Hadeeths in Al-Kufi are more in number than all the total authentic Hadeeths in all the six books of Sunni Hadeeth الصحاح الستة. 
Number of unrepeated narrations in Saheeh al-Bukhari is 2602 and in Saheeh Muslim 4000, while the number of unrepeated narration mentioned in both Bukhari and Muslim is 2514 narrations.

Al-Kafi alone has 16199 narrations.

Wassalam.