IMHO you have run into a twofold problem: Faulty ignition of the rifle barrel is nowadays a quite common problem with old 9.3x72R drillings, with hammer drillings occuring more often than not. When these drillings were made, the cartridges were loaded with large .254" diameter Berdan primers, made of thin copper and much more easily dented than modern large rifle primers. A quite common cure is to use large pistol primers, which are more sensitive. As the Max pressure of the 9.3x72R is well below that of magnum revolver cartridges such as .44 Mag, there is no problem here. Further, coil-spring striker lockwork drillings are quite rare and were never popular for good reason: The force of the light strikers powered by thin coil springs was always marginal for igniting even the soft primers of the old times, so they were prone to misfires even then. Apparently a former owner of your drilling tried to solve the problem by replacing the original springs with stronger/thicker ones, now creating a new problem with the spring to spring interference. I fear, as the original makers of coil spring striker drillings could not solve the ignition problems, even at the times of softer primers, you too will not succeed in making your drilling completely reliable.
