Join Date: Jul 2010
Location: St. Louis, MO area.
Eventual would probably be the most accurate. The three screw lock seemed to be dominate on early guns/locks - of English manufacture. But it's not a hard fast rule. A good example would be the British, First Model Brown Bess musket of 1728 used only two screws. But the British Sea Service musket of about 1738 continued the use of three screws. I guess the third screw was eventually faded out and simply considered unnecessary.
That lock you just posted looks typical dog lock but with a bit of Spanish/Portugese influence. Very cool.
Occassionaly, you will find a later dog lock that has a half-cock saftey feature on the lock tumbler (like a regular flintlock) but still retaining a dog safety catch as an extra safety. Curious.