The Protogunner is one of the vehicles from Metal Slug 6.
The Regular Army's engineers, using the schematics of the Rebel Army's LV Armor, started to design a new model of Super Vehicle, the Slug Gunner. They produced this prototype unit for testing purposes. Although it doesn't have any kind of protection for the operator nor the Gatling gun and pile-bunker weapon in the final design. However, it still retains its 180mm multiple cannon on its front, along with a pair of 10mm Vulcan cannons on the side. By holding the fire button with this slug (with any character), the Vulcan cannons will be Vulcan Fixed (Tarma's ability in MS6), which makes it lock in place and allowing it to continuously fire without moving the Vulcans themselves. This is helpful as the player can freely move and attack at the same time, without being pressured to keep their Vulcans on their target (like walking backwards and shooting etc.).
Despite having less armor and that it is a prototype of the Slug Gunner, it is much lighter and maneuverable than the latter. Although it does not have the jet pack that allowed it to double jump like the final product, it still jumps reasonably high even without it.
- The SVX-15D Slugnoid also has some things in common with the Protogunner; both are combat mechs developed by the Regular Army, equipped with a pair of Vulcan cannons and a main cannon, and are able to jump. The only differences are the types of main cannon used, the jumping methods, the firing rates of their Vulcans, and their movements (the Slugnoid walks sideways while the Protogunner could walk both forwards and backwards).
- In Metal Slug Defense, the Protogunner is a relatively fast-producing heavy walker capable of long range fire support. It has an average amount of HP comparable to the finalized Slug Gunner with decent armor and damage. When destroyed, there is a chance Ralf jumps out before it explodes and fights from the ground; it is unknown on how upgraded this Ralf is. The height of its jump special allows it to very easily land hits on passing air units including R-Shobu, although it doesn't deal enough damage in one shot to destroy one.
- In Metal Slug Attack The driver is replaced from Ralf to Tarma, this is probably because Ralf is too powerful when he was jump out and replace Protogunner role.
|Mechanized||SV-001 (Metal Slug) | Slug Copter | Slug Flyer | Slug Sub | Astro Slug | Slug Gunner | Slugnoid | LV Armor | Walking Machine | Slug Mariner | Drill Slug | M-15A Bradley | Metal Claw | Forklift | Slug Mobile | Augensterm | Protogunner | Slug Digger | Slug Trolley | Slug Armor | Slug Gigant|
|Animal||SV-Camel | Elephant Slug | Ostrich Slug | Donkey Slug|
|Other||Middle-Son 1986 | Middle-Son 1999 | Motorcycle | Regular Army Helicopter | Landseek | PA33-21 Boat | RA-TTT | Rootmars|