Very detailed dual artillery turret.
Included files :
.max (max 2010) file - with pivots set to allow both barrels to rotate as shown in renders above.
.obj file - direct export from the above .max file
.3DS file - direct export from the above .max file

Animation info : in the .max file, the barrels are named 'barrel_group1' and 'barrel_group2', they rotate along the Y axis between 0 and 30 degrees. The objects named 'turret_armor1' and 'turret_armor2' are small armor flaps that rotate along the Y axis between 20 and 50 degrees, together with the barrels.
For both the .obj and .3ds file you will have to set the pivot points and proper grouping manually first.