300 pound club 

Pertaining to a class of weightlifter who succesfully lifts a sum of 300 or more pounds either at-once or cumulatively. Typically, a high school football player is awarded a special patch signifying their entry into the club upon lifting this weight.

Fernando bench pressed 320 pounds and recieved his 300 Pound Club patch.

300 pound club by S. G. April 17, 2006

300 inline 6 

The most reliable gasoline engine ever produced it can take one hell of a beating and still go strong it may not have the most horsepower but it will pull the world down no questions asked. Not even whisilin diesel could kill this engine if he tried

Once this world comes to an end there will be 2 things on this planet left and that is a cockroach and a 300 inline 6.

300 inline 6 by Jklg25 July 1, 2022

300 kick 

An extremely hard kick straight to the chest, like the one King Leonidas does to the Persian messenger in the movie 300. Some people like to quote Leonidas saying "This is Sparta!" before they do it.

Jim: Eat my last chicken nugget, and receive a swift 300 kick to the chest.

James: (eats the nugget while giggling)

Jim: (stops his heart with a 300 kick)

300 kick by SamPick January 2, 2009

300 camp 

Most biggest gang in the locks as in they run the locks

them 300 camp niggas big

300 camp by Kamboo January 31, 2021

300,000 dollar golf swing 

A heist job with a large enough payout to afford retirement. Can also be used for a last job.

“Who knows maybe after this I can finally afford that 300,000 dollar golf swing

300,000 dollar golf swing by Skhizy December 17, 2020

300 bucks 

Meme phrase from Van Darkholme interview, famous gachimuchi actor

Gachimuchi — an Internet meme and subculture that originated in August 2007 on the Japanese video hosting Nico Nico Douga. In 2016, the phenomenon had spread all over the Internet. The meme is based on low-budget gay porn films of the 1990s and includes, among other things, a large number of mashup parodies of popular music compositions and clips created using audio fragments of porn videos included in the fandom. (from Russian Wiki)

Van: fisting is 300 bucks
Billy: son, you're true dungeon master!

300 bucks by vzlomed February 25, 2023

300% done 

When you're 100% done three times.

Jake: Why are you looking so down?
Jack: I lost 100 bucks in a bet 3 times. I'm 300% done with life

300% done by Binaryomlette April 30, 2016