How can the verse say that Dan did not have an inheritance until now? Sefer Yehoshua 19:40-48 discusses their inheritance!
Rashi: They did not have an inheritance proper for them in what was conquered - "va'Yetzei Gevul Bnei Dan Mehem" (Yehoshua 19:47). 1
Radak: What the lottery gave to them was too small for them.
Malbim: They did not dispossess the Kena'ani, and the Kena'ani took it back from them. This is because their inheritance was not amidst Bnei Yisrael, rather, outside (on the western border - Malbim Yehoshua 19:47).
This is like Radak explained there. Rashi there explained that Dan took some here, and the lottery gave to them also elsewhere, far from their inheritance, and other Shevatim interrupted in between. (PF)
When did this occur?
Rashi: Our verse supports what I cited above (17:1) from Seder Olam, that it was immediately at the beginning of the Shoftim. 1
Radak: This episode supports what I said above (17:1), that it was not in the days of Osni'el 2 . In the days of a Shofet, Hashem saved them and they served Hashem all the days of the Shofet. Rather, Pesel Michah, and Bnei Dan setting it up, and Pilegesh b'Giv'ah were after Shimshon died and before Eli.
I.e. we cannot say that Dan did not have enough land, and did nothing about it for over 300 years! (PF)
Radak: In Yiftach's last year, he sent to Amon, 300 years after we conquered Sichon. In the 140 years remaining until Binyan Beis ha'Mikdash were the years of Avtzan (seven), Eilon (10), Avdon (eight), Shimshon (20), Eli (40), Shmuel (20, according to Seder Olam), Sha'ul (two and a half) David (40). This is 149 in all! There is no verse for Shmuel; really, his 20 years include seven of David and two of Sha'ul. You cannot say that Shimon's years enter into Eli's. Eli was 58 when he became judge, and was a Chacham in the chain of Kabalah (from Pinchas to Shmuel. Surely Shimshon would not be called the Shofet during Eli's reign!) Seder Zemanim (a Perush on Seder Olam) - the Radak had an errant text of Seder Olam.