|Specifics: This is for Crossing Over|
The Proton Pistol appears as a secondary weapon of Winston Zeddemore during the events of the Infestation. Winston has exclusive use of it because of the four Ghostbusters, he is the best shot, so he'd get the "precision" blaster.  It appears to be strapped to either leg during busts.
The Proton Pistol was first seen used by Winston against a Zombie near 20 Clinton Avenue. The Zombie absorbed the single stream and imploded. Winston also later pulled the Proton Pistol on Britt when she appeared to them in the Firehouse basement. Since then, it is usually equipped by Winston on cases. During the Fantastic Land case, Winston used the Pistol to shoot Peter Venkman while he was possessed by the Hungry Manitou, likely suffering some short term memory loss and violent bowel evacuation.
By the time of Winston and Tiyah Clarke's wedding, the Proton Pistol was yielded by Special Agent Melanie Ortiz. In the battle against The Sandman in a dream state, Winston visualized the Proton Pistol and opened fire with it. Melanie used the Proton Pistol against Loftur Þorsteinsson in the Central Park meeting but he easily blocked its Proton Stream with an Icelandic rune. Lacking time to trap ghosts as they jumped from dimension to dimension to slow down The Collectors, Winston used his Proton Pistol to temporarily atomize ghosts like Shibano. After The Collectors found Winston and Leonardo in a war torn dimension, Winston fired at them with the Proton Pistol at maximum power while Leonardo used his thrower. It wasn't enough to atomize them. Luckily, they were summoned away by Darius Dun at the moment.
If the Proton Pistol and Particle Thrower are used at the same time, the strength of the stream is split between the two. 
- For Ghostbusters: Infestation, Editor Tom Waltz requested Winston use the Arm Mounted Proton Pack again. Erik Burnham misunderstood and it was referred to as 'pistol.' Artist Kyle Hotz then based the gun on the Proton Pistol from Extreme Ghostbusters. 
- On page 15 of Teenage Mutant Ninja Turtles/Ghostbusters Volume 2 Issue #2, Winston now has two Proton Pistols instead of one while in the war dimension.
- "Ghostbusters: Infestation 1"
- "Ghostbusters: Infestation 2"
- Ongoing Series
- Teenage Mutant Ninja Turtles Ghostbusters
- Ghostbusters Get Real
- Issue #1
- Convention Cover only
- Issue #1
- Ghostbusters Annual 2015
- "Daydreams and Nightmares!"
- Ongoing Series
- Volume Three
- Ghostbusters Annual 2017
- Answering The Call
- Ghostbusters 101
- Teenage Mutant Ninja Turtles/Ghostbusters Volume 2
- ↑ Erik Burnham post on GBFans
- ↑ Winston Zeddemore (2017). IDW Comics- "Teenage Mutant Ninja Turtles/Ghostbusters Volume 2 Issue #4" (2017) (Comic p.1). Winston Zeddemore says: "Power's maxed... but we're still splitting the stream and these guys are too much for just one Proton Pack."
- ↑ Big One Podcast Erik Burnham Interview 8/17/12, 40:48-41:28