multibarrel
adjective
mul·ti·bar·rel ˌməl-tē-ˈber-əl 
-ˌtī-
variants or multibarreled
ˌməl-tē-ˈber-əld
-ˌtī-
of a firearm
: having two or more tubes for discharging ammunition
a multibarrel gun
Word History
First Known Use
1894, in the meaning defined above