It was a time-consuming and tedious process, even with AI assistance, but I'm really happy with the result, and I hope others who have been looking for this sound will enjoy it too!

INSTALLATION

1. Download the .zip file from the link below.
2. Extract the downloaded archive.
3. Open the BO3 Hitmarker Sound T6 folder.
4. Copy or move the cmn_root.all.sabl file into the sound folder located inside pluto_t6_full_game. Do not use the T6 folder located in the Plutonium installation directory.
5. When prompted to replace the existing file, click Yes.

TIP: Before replacing the original cmn_root.all.sabl file, make a backup of it so you can restore the original BO2 audio if needed.

That's it! Enjoy the BO3 hitmarker sound in BO2.

DOWNLOAD:
Hhttps://www.mediafire.com/file/cvbng6255daq3pp/BO3_Hitmarker_Sound_T6.zip/file

TIP: I had to modify the download link because the forum only allows users with at least 1 reputation point to post links. I added an extra "H" at the beginning of the URL to prevent it from working as a clickable link. Copy the URL, remove the extra "H" at the beginning, and paste the corrected link into your browser to download the file.