Why Sentinel prime did not use his cosmic rust gun again ?

Sentinel Prime (Transformers Film Series)

Sentinel Prime (ROTF) - Transformers Wiki

26 minutes Video of Transformers Details that you Surely missed

Wheeljack in Transformers: Rise of the Beasts is an IMPOSTOR

Wheeljack in Transformers: Rise of the Beasts is an IMPOSTOR

Transformers: Cosmic Rust, Explained

Wheeljack in Transformers: Rise of the Beasts is an IMPOSTOR

Why Sentinel prime did not use his cosmic rust gun again ?

Who would win, Sentinel Prime (Transformers: Dark of the Moon) vs

Sentinel Prime deserved to die in DOTM : r/transformers

ArtStation - Sentinel Prime Rust Cannon

How Megatron Got His New Form ?

The Cosmic Rust Atrocity by SuperHeroTimeFan on DeviantArt