Grading: (1) Its narrators are thiqah (trustworthy), but there is a disagreement over Husayn (bin Abd al-Rahman al-Sulami) about whether it is "connected or mursal".
Technical note / Defect ('illah): Jarir (bin Abd al-Hamid al-Dabbi) and Warqa' (bin Umar al-Yashkuri) narrated it "mawsul" (connected), as it is with the author (al-Hakim). But Khalid bin Abdullah al-Wasiti, Sulayman bin Kathir al-Abdi and Abu Ja'far al-Razi differed from them and narrated it as "from Abd al-Rahman bin Abi Layla, from Usayd bin Hudayr" (that is, without mentioning the link of Abu Layla). And Abd al-Rahman bin Abi Layla did not hear from Usayd bin Hudayr, as al-Dhahabi said in "Siyar A'lam al-Nubala'" (1/ 341) and Ibn Abd al-Hadi in "Tanqih al-Tahqiq" (346).

Grading: Al-Dhahabi regarded the chain of the "mawsul" (connected) narration as strong in "Tahdhib Sunan al-Bayhaqi" (6/ 137).

Reference / Source: Al-Bayhaqi recorded it (8/ 49) from Abu Abdullah al-Hakim, from Abdullah bin Muhammad al-Saydalani, with his chain.

Reference / Source: Abu Dawud (5224) recorded it through the route of Khalid bin Abdullah al-Wasiti, from Husayn bin Abd al-Rahman, from Abd al-Rahman bin Abi Layla, from Usayd bin Hudayr (a man of the Ansar).
Details of the narration: He did not mention "Abu Layla" (that is, the link between Ibn Abi Layla and Usayd was dropped).

Corroborating chains and supporting reports: Khalid al-Wasiti was corroborated in this (chain) by Abu Ja'far al-Razi (in al-Tabarani's "al-Kabir" 557) and by Sulayman bin Kathir al-Abdi (in Ibn Asakir's "Tarikh Dimashq" 9/ 89).

Important point: Other hadiths have also been narrated about the Prophet (peace and blessings be upon him) giving "qisas" (retaliation) against his own noble self, among them the following:

Reference / Source: Ahmad (1/ 286), Abu Dawud (4537) and al-Nasa'i (6953) narrated from Umar bin al-Khattab (may Allah be pleased with him) that he said: "I saw the Messenger of Allah (peace and blessings be upon him) allowing retaliation (qisas) against himself."
Grading: Its chain is "hasan" (good).

Reference / Source: And among them is the narration which will come later with the author at number (8142), in the story of a Bedouin whom the Messenger of Allah (peace and blessings be upon him) scratched unintentionally.

Grading: Its chain is "da'if" (weak).

Reference / Source: And among them is what Ibn Ishaq narrated (as in "Sirat Ibn Hisham" 1/ 626) in the story of Sawad bin Ghaziyyah: that the Prophet (peace and blessings be upon him) poked him in the stomach while straightening the rows on the day of Badr, so he said: "O Messenger of Allah, you have hurt me, and Allah has sent you with truth and justice, so let me take retaliation." So the Messenger of Allah (peace and blessings be upon him) uncovered his stomach and said: "Take your retaliation." Sawad embraced him and kissed his stomach. He (peace and blessings be upon him) said: "What made you do this, O Sawad?" He said: "O Messenger of Allah, what you see (the battle) has come upon us, and I wanted my last moment with you to be that my skin touches your skin." So the Messenger of Allah (peace and blessings be upon him) prayed for good for him.
Grading: Its narrators are thiqah (trustworthy).
Details of the narration: Ibn Sa'd (3/ 478), in the biography of Sawad bin Ghaziyyah, narrated something like this story with a different wording, in which it is not stated that it happened on the day of Badr, and the person in the story is named "Sawad bin Amr". It seems that Ibn Sa'd counted Sawad bin Ghaziyyah and Sawad bin Amr as the same person, since "Amr" is among his forefathers, and he may sometimes have been attributed to his grandfather.

Note / Clarification: "al-kashh": the waist, the part of the side between the ribs and the hip (flank).