The E-11 is the standard issue Imperial blaster. Stormtroopers and Sandtroopers alike carried this blaster in all 3 original trilogy movies.

ANH E-11 Blaster
The ANH and ESB E-11s were based on the WWII Sterling L2A3 machine gun.

 

ROTJ E-11 Blaster
The ROTJ E-11s were based on the MGC (Model Gun Company) replica Sterling.

 

DLT-19 Heavy Blaster
The DLT-19 is based on a German MG-34 with bipod.