Kirk Hammett

At 6:33 from his own String Theory by Ernie Ball, he talked about what kind of guitar strings still stay in tune and not broken when he use the whammy bar. Until he takes the 3rd pack, he's like: "What is that pack? An Ernie Ball Super Slinky! YES! The Ernie Ball Super Slinky!! That's what we need!!"

In this publication from Ernie Ball's account it is proofed that Kirk is using their new set of strings.

Kirk Hammett uses Ernie Ball Regular Slinky Guitar Strings (10-46), as shown in a photo from Fbcdn.

According to Metallica's official website (archived by WayBack Machine on January 18th, 2013), Hammett uses Ernie Ball RPS 11-48 guitar strings.

In 2016, Hammett was featured in Ernie Ball's String Theory. Hammett explained the use of mixed set of 10s and 11s. Though RPS model is not explicitly mentioned, the RPS strings can be seen at 2:08 and 5:38.

Kirk Hammett uses Ernie Ball RPS Regular Slinky Guitar Strings (10-46), as showcased on Ernie Ball's Instagram, featuring his workbench in a post with the hashtag #iplayslinky.

Ground Guitar states that Kirk Hammett uses Ernie Ball Ultra Slinky Guitar Strings (10-48). Additionally, when I attended his Gibson book event and asked him directly, he confirmed that he uses these strings.