From the San Bernardino National Forest Recreational Shooting
Areas with designated sites for target shooting (when permitted) include:
Forest Road 1N09 East of Highway 330 (CLOSED for fire rehabilitation work)
Forest Road 3N14 North of Highway 38 (OPEN)
Forest Road 2N02 East of Baldwin Lake Road (OPEN)
Forest Road 5S07 North of Highway 74 (OPEN)
This is, of course, in addition to hunting in season.
Note the caveats mentioned on that page before you head up there.