If someone completes a major section of Talmud Torah that is not a formal unit (eg., Basar BeḤalav), may/should one make a Siyum?
Rav Moshe writes in his Igros Moshe OH 1:157 that if someone did learn and feels accomplished then that calls for celebration but he also mentions that it took some time and it seems from the tshuva that the mikra was completed and the Rishonim were used for iyun. see inside for mekoros.
Rav Eliyashiv is quoted in the Sefer Va'yishma Moshe and held to be machmir and not make a syium on Nach.
In this lecture, the speaker quotes R' Moshe Feinstein that anything that you do that you feel proud of accomplishing — even someone who learned one daf of gemara, if it was hard for him — you can make a siyum on it.
According to the Guidlines series (by Rabbi Elozor Barclay and Rabbi Yitzchok Jaeger) in both the volume on the 3 weeks and the volume on Pesach say that a siyum to permit breaking the fast of the firstborn and eating meat in 9 days are one of the following:
- A tractate of Talmud
- A seder of Mishna
- A book of Tanach learned b'iyun (b'iyun is not defined there)
- A tur of Shulchan Aruch