In the early days of breechloading guns primers had not been perfected and often they were quite soft. Sometimes strikers would stick in a fired primer and not retract. Several maker's solutions to eliminating stuck strikers was to design a mechanical means to force the striker back when cocking the hammers. Your Tolley is one variation. I own a W W Greener non retracting hammer gun with his solution which he called his "self acting striker", patented in 1868.

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