This is the 3803rd most frequent Japanese word.
ぶち込ん
"ぶち込ん" means "to throw in forcefully" or "to shove in."
Here 'ぶち込んだ' suggests forcefully or quickly inserting information into one's mind.
彼は問題の答えを一瞬で頭にぶち込んだ。
He put the answer to the problem into his mind instantly.
In this sentence, 'ぶち込んだ' refers to forcibly or hastily putting something into another object.
郵便屋さんが手紙をポストにぶち込んだ。
The mailman shoved the letter into the mailbox.
Here 'ぶち込んだ' indicates forcefully throwing or ejecting something into a place.