EXCLUSIVE

George Zimmerman was on the hunt today -- for a shotgun ... TMZ has learned.

Zimmerman went to Kel-Tec in Cocoa, Florida ... a gun manufacturing company. We're told he was asking questions about the legality of buying a shotgun -- specifically, the Kel-Tec KSG.

The gun in question is a tactical shotgun, often used for home defense. It holds 12 rounds of 12 gauge shells.

And this is interesting ... Kel-Tec manufactures the PF-9 gun -- the pistol Zimmerman used to kill Trayvon Martin.

We're told the owner's son took Zimmerman on a tour of the grounds, including the area where the firearms are assembled. The photo of Zimmerman and an employee (above) was taken inside the assembly plant.

It's unclear if he actually bought the shotgun while he was there.