what is the exact meaning of "部長が自分のミス俺のせいにしゃがってさ" in below sentence I don't understand exactly the meaning of "" the whole sentence is: ! the meaning in the text is: today, the head of my department tried to blame me for his screwup. “This is wrong!” I said. “A chief is a chief because he protects his subordinates!” but I want to know the grammar points of the aforesaid sentence and if the meaning is correct or not.

If it's that's troubling you, it's not but , which is (masu-stem of ) + .

If it's that's troubling you, see: form at end of phrase but not being used for requests

This sentence uses the AB ("to make A B", "to turn A into B", "to pretend A as B") construction, although has been omitted:

> ****
> The chief turned his own error into my fault.
> → The chief blamed me for his own mistake.