The Sign of Four is a British 1923 B&W detective movie, losely based on the famous novel by Arthur Conan Doyle. It is directed by Maurice Elvey and stars Eille Norwood as Sherlock Holmes and Arthur M. Cullin as Dr. Watson. This is the final installment in a series of forty-seven silent films (45 shorts and 2 features), starring Eille Norwood as Holmes.
The following weapons were used in the film The Sign of Four:
A snub nose revolver of Bulldog family is seen in Holmes' apartments.
Webley .38 Mk III
Dr. Watson (Arthur M. Cullin) carries a Webley .38 Mk III revolver during the visit to Dr. Sholto.
Smith & Wesson Model 2 Double Action
Dr. Sholto (Humberston Wright) carries a compact top-break revolver; Smith & Wesson Model 2 Double Action seems to be a good guess. Dr. Watson (Arthur M. Cullin) takes the gun from Sholto and uses it to break a door lock.
Pocket revolver
During the boat chase Prince Abdullah Khan (Fred Raynham) holds a pocket top-break revolver of unclear model.
Pistols
Webley & Scott Metropolitan Police
During the confrontation with Jonathan Small and his pygmy accomplice, Sherlock Holmes (Eille Norwood) uses a Webley & Scott Metropolitan Police pistol.
Webley & Scott Model 1909
After Holmes shot the pygmy, he aims his pistol at Jonathan Small, and the gun switches from full-size Webley to a pocket model (and later back to Metropolitan Police model). It's hard to say if it has exposed hammer or is hammerless.
Rifles
Unidentified rifle(s)
Guards of Andaman Islands Prison Settlement carry some rifles that aren't seen clear enough for positive identification.