Above - 1921 tradepaper ad for one of Horner's early westerns, 'NEATH WESTERN SKIES (Western Classics, 1922) which starred Monte Montague, Ena Gregory and tall and thin Nelson McDowell.
At the time of this film, Horner was general sales manager of Western Classics, but would soon become the boss. Note the spelling boo-boo with Montague's first name (he's Monte, not Monti).
Not hero material, Montague became a prolific player in Universal serials and henchman roles in many sound westerns.
Monte Montague - circa 1941
Above is a 1923 tradepaper ad for Horner silents, and he's now Robert Horner Pictures, Inc.
Bottom left corner is George Chesebro and Eva Novak is pictured in the bottom right. Chesebro worked in about a dozen of Horner's sound westerns. Novak and Chesebro were witnesses at the September, 1923 marriage of Horner to Frieda Bohnn.
In addition to westerns, Horner churned out melodramas and action flicks. Above is a 1924 trade ad for George Larkin's series for Bob Horner Productions and released through Rayart.
From the August 27, 1924 Film Daily: "W. Ray Johnston of Rayart has closed with Bob Horner Prod., of Los Angeles for a series of six stunt pictures based on newspaper reporter stories. The first has already been completed, is called 'Midnight Secrets' and stars George Larkin."
Above is a 1927 tradepaper ad for Horner silents. "Pawnee Bill, Jr." was played by Ted Wells and "Kit Carson" was Boris Bullock / William Barrymore.
THE MANSION OF MYSTERY serial was completed and released in late 1927 and there are theater ads for various chapters. William Barrymore had the lead, Horner directed, and distribution was handled by William M. Pizor. MANSION is among the lost / missing serials.
Horner must have liked Barrymore - or his salary demands were cheap - as he appears in about fifteen Horner silent and sound films.
Barrymore also had the misfortune of doing four sound oaters for Denver Dixon / Victor Adamson, including the role of the "Rawhide Terror" in the chaotic mess THE RAWHIDE TERROR (Security, 1934).
Elia Bulakh (1899 - 1979) used screen names of Boris Bullock / William Barrymore. Image above from Horner's THE WHIRLWIND RIDER (American Pictures, 1933) which starred Buffalo Bill Jr.