A blunderbuss with an early lock

[Philip]

Fernando,
Or I should say, not all dogs are created equal.
1. Norman could not be correct on this. The north European dog-lock, of which you have an example, is not developmentally connected to any of the dog-locks of the Mediterranean or Oriental worlds (the agujeta, the Sinhalese snap lock, etc) for the simple reason that the former has an internal mainspring, and all of the latter have external springs.

2. Furthermore, the sear (the assembly that releases the cock upon pull of trigger) is entirely internal on the northern dog-lock. It is a one-piece L shaped arm under spring tension, with studs that engage a tumbler or nut on the cock's axis bolt. The sear system on the agujeta (either the Hispanic or Algerian types) is a 2-piece assemblage with a stud or nose that engages the cock directly through an aperture in the lockplate; on this type of lock there is no tumbler. See Blackmore, pp 112-15 for text and diagrams.

3. I'm not sure whether the Sinhalese snaplock is a direct descendant of the agujeta. A comparison of the sear systems is in order, and I can't find this aspect illustrated in any of my reference books. Lavin's article "Spanish Agujeta-lock Firearms" in ART, ARMS AND ARMOUR (ed. Robert Held, 1979) emphasizes that the Iberian version typically has a wheellock-derived lockplate profile -- trapezoidal with an obtuse point at the bottom, AND is equipped with two bridles or support bridges for the cock and frizzen pivot screws. The Sinhalese lock has a different plate and lacks a frizzen bridle. Daehnhardt, in ESPINGARDA FEITICEIRA, contends that the Sinhalese lock originates with the Italian miquelet "alla romana" which may well be the case. Again, a comparison of the sear design will help resolve this.

Note that the trapzoidal lockplate is absent on the Algerian version of the agujeta although functionally it remains the same, and even inherits the big alligator jaws and the wing-top screw on the cock of the later Spanish versions. From this we can expect some stylistic changes when the Sinhalese developed their snaplock, whether it be from prototypes originating in Spain, Italy, or even Portugal.

Sorry if this sounds so convoluted and geeky, if you need any clarification please let me know.