Sayyiduna Imran bin Husayn (may Allah be pleased with him) said that the Messenger of Allah (peace and blessings be upon him) forbade selling weapons in a time of tribulation (fitnah).
It is known as marfu' only through the narration of Bahr bin Kunayz al-Saqqa, and Bahr al-Saqqa is da'if (weak); he is not used as evidence.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب البيوع / 10781