Firstly I am not a preterist. I consider preterists almost as wrong as futurists.
The 483 years can only have ended at the baptism of Jesus, when John the Baptist presented him as the Lamb of God who takes away the sins of the world. At the same time a voice from heaven said this is my beloved son, shortly followed by Jesus announcing "The Spirit of the Lord is upon me, because he hath anointed me to preach the gospel to the poor; he hath sent me to heal the brokenhearted, to preach deliverance to the captives, and recovering of sight to the blind, to set at liberty them that are g, To preach the acceptable year of the Lord."
To set the captives free must mean Jesus was announcing the jubilee.
Now a question for you. What events do you say have not happened that will take place during the70th week?
Most of the Olivet Discourse (apart from the Luke portion concerning Jerusalem which happened 66-70 AD)
The rise and rule of the "antichrist"
The abomination of desolation standing in the holy place (corresponding to Paul in Thess.)
The angels going throughout the world, the "false prophet".
The salvation of the entire nation of Israel ans spoken in Jeremiah 31 and Daniel
24 Seventy weeks are determined upon thy people and upon thy holy city, to finish the transgression, and to make an end of sins, and to make reconciliation for iniquity, and to bring in everlasting righteousness, and to seal up the vision and prophecy, and to anoint the most Holy.
25 Know therefore and understand, that from the going forth of the commandment to restore and to build Jerusalem unto the Messiah the Prince shall be seven weeks, and threescore and two weeks: the street shall be built again, and the wall, even in troublous times.
26 And after threescore and two weeks shall Messiah be cut off, but not for himself: and the people of the prince that shall come shall destroy the city and the sanctuary; and the end thereof shall be with a flood, and unto the end of the war desolations are determined
27 And he shall confirm the covenant with many for one week: and in the midst of the week he shall cause the sacrifice and the oblation to cease, and for the overspreading of abominations he shall make it desolate, even until the consummation, and that determined shall be poured upon the desolate.
A) Israel has not finished THE transgression
B) they have not made an end of sins
C) Everlasting righteousness has not been brought in yet
D) Israel has not anointed the most holy!
E) While Rome has destroyed Jerusalem and the Sanctuary- the prince (antrichrist) has not amde a 7 year covenant with the many yet!
F) There has been no ceasing of the sacrificial system after 1/2 of a 7 year covenant. Nor for teh overspreading of abominations!
There are many more.